NASA Part 2 Technical Memorandum Aircraft Noise Prediction Theoretical Manual William E. Zorumski Langley Research Hampton, Center Virginia NILq Nateonal Aeronaul_cs anO Space/_Om_ nJs_raT_on _mNI II_mltkm Tge2 Tedmicd arm_ 83199 Program t pl ,. mG pP.GE NOT Ftt..eiW CONTENTS Part I. INTRODUCTION 2. AIRCRAFT 3. 4. 5. 6. 7. ......................... FLIGHT 2.1 ATMOSPHERIC 2.2 GEOMETRY 2.3 FLIGHT DYNAMICS I-I ........ MODULE .................... MODULE 2.1-I ...................... DYNAMICS PROPAGATION MODULE 2.2-1 .................. 2.3-1 EFFECTS 3.1 ATMOSPHERIC 3.2 GROUND SOURCE I* ABSORPTION REFLECTION NOISE 4.1 FAN 4.2 CORE 4.3 TURBINE 4.4 JET 4.5 AIRFRAME MODUL2 AND ............... ATTENUATION MODULE 3.1-1 ......... 3.2-1 PARAMETERS NOISE PARAMETERS NOISE PARAMETERS NOISE NOISE MODULE MODULE PAFJLMETERS PARAMETERS NOISE ................ ............... MODULE MODULE PARAMETERS 4.1-1 4.2-1 .............. 4.3-1 ................ MODULE 4.4-1 ............. 4.5-1 PROPAGATION 5.1 PROPAGATION 5.2 GENERAL RECEIVED MODULE SUPPRESSION .................... MODULE 5.1-1 ............... . 5.2-1 NOISE 6.1 NOISE LEVELS 6.2 EFFECTIVE MODULE NOISE .................... .MODULE 6.1-1 .................. 6.2-1 .................. 7.1-1 UTILITIES 7.1 ._"HEP_MODYNAMIC *Chapters I to UTILITIES 7 are published iii under separate cover. + Part 8. 9. NOISE SOURCES 8.1 FAN 8.2 COMBUSTION 8.3 TURBINE 8.4 SINGLE 8.5 CIRCULAR 8.6 STONE 8.7 DUAL 8.8 AIRFRAME 8.9 SMITH PP_DICTION 9.1 2 ICAO NOISE MODULE ..................... NOISE NOISE .MODULE STREAM SHOCK NOISE STREAM BUSHELL 8.2-1 ................... JET CELL .MODULE NOISE NOISE MODULE CCANNULAR NOISE AND .................. CIRCULAR JET JET MODULE 8.1-I MODULE MODULE 8.3-1 .......... 8.4-1 ........... 8.5-1 .................. JET NOISE MODULE 8.6-1 .......... 8.7-1 ................... TURBINE NOISE MODULE 8.8-1 .......... 8.9-1 PROCEDURES REFERENCE NOISE-PP/EDICTIO:_ PROCEDURE iv (!978) ..... 9.1-1 8. NOISE SOURCES 8.1 FAN NOISE MODULE INTRODUCTION l_ne an Fan axial oped Noise flow by M. predict F. the Module predicts compressor or Heidman sound (ref. spectra the fan. The 1). The a function as broadband method noise is method emploTs of and based on pure the empirical frequent/ and tones method for devel- functions polar to direcrivity angle. The rate total fan noise, inlet stator The tone interaction The Module flow or required. tones. function tivity other by The of the user. is executed output is frequency, fan it noise is are several table by the the each noise is Ae engine a,b exponents B number C mean Zoo inlet cross-sectional not that reference of rotor ambient rotor the directivity d fan F pc_er f frequency, rotor m2 m2 (ft 2) blades blade speed D area, Area, of chord, m sound, m/s function diameter, m function Hz 8.1-1 (ft) a single (ft) (ft/s) entrance values of acoustic to output (ft 2 ) fan Parameters parameters of and SYMBOLS fan Noise set tables. A rotor- into The Fan angle, assumed so sepa- tones, discharge combined mean-square directivity introduced six broadband distortion and user-provided for of flow parameters. provided from inlen angle. Additional polar Although angle, a inlet sources once noise are noise, directivity of be the selected tones, noise input summing broadband each can module angle. directivity widn requires The parameters. a All for parameters directly by sources discharge spectrum method predicted component interaction noise, i/3-octave-band exit is six rotor-stator combination and noise components. with table input pressure azimuthal vary are the direcazimuthal is compatible as fb blade passing G constant i inlet K constant k,£ inlet Md fan frequency, Hz matrix guide vane flow index distortion rotor indices design relative point tip Mach Mach number fan rotor relative tip M t fan rotor tip number flow Mach M aircraft m mass N rotational N e number n tone flow r s distance r* L dimens S tone S roter-stator V n_n%oer polar number (slugs/s) Hz acoustic pressure, pressure, 2 source × to Pa o2c 4 observer, (4.177 m source _ temperature m rise to observer, temperature, stator (ft) across K fan, (°R) vanes factor parameter /irect_vlt'_" angle, deg _.I-2 10 -7 Ib/ft 2) (ft) function spacing, of re 10 ..5 from distance _pectr_m frequency (l,Md) number icnless cut-off point engines from total ambient kg/s harmonic reference T rate, of Pref Mach max design (ll)) number speed, mean-square at and n,m_ber Mach <p2>" (lO) number index, M r Mach (eqs. K (oK) re _e .J , acoustic power, _ref reference O_ ambient re p c_A 1 x 10 -12 power, density, azimuthal kg/m 3 directivity W (7.376 (ib/ft x 10 -13 J, ft-lb/s) 3) angle, deg Superscript: * dimensionless quantity INPUT The Noise fan parameters Parameters computation of sound angle, and azimuthal values for the of rotor flow blades, metric description design engines, default table. of The the reference H e number of distance establish the area, guide fan rotor are the engine are required. are m2 polar the spacing observer of are given vane index, tip relative required The table source to m (ft) S Fan Geometry t A fan 3 number d * fan I inlet Md fan inlet of rotor guide rotor inlet flow cross-sectional rotor re rotor-stator V n_._nber of index relative tip distortion Mach index spacing, stator Ae _e t S re blades diameter, vane area, vanes 8.1-3 re C number at design point number inlet for Mach the area, range I. (ft 2) observer, for variable area, engines from Fan independent reference in the required directivity cross-sectional inlet Finally, output frequency, diameter, parameters the conditions inlet vanes, fan. to engine fan rotor-stator input A e arrays rotor the distance of levels. The and either Ambient stator fan point, and values of from user. directivity index, at the pressure number distortion required or output number of are Module geo- number and Fan e mass flow N* rotational AT* total rate, Noise re Parameters O_c_A speed, re temperature c e /d rise across Ambient ambient C speed aircraft Mach ambient P_ of T Conditions sound, m/s kg/m 3 (ft/s) (slugs/ft Independent polar re number density, frequency, fan, 3) Variable Arrays Hz directivity azimuthal angle, directivity deg angle, deg OUTPUT The output pressure muthal is as a of directivity provided _nodule of for the is In frequency, 9 polar O azimuthal of polar the mean-square directivity the nozzle pseudo-observer and azi- distance rs exit to Noise pseudo-observer, m {ft) Table Hz directivity angle, directivity deg angle, deg 2 <p2(f,9,,)>" acoustic angle, Module. Fan f table addition, Propagation from a frequency, angle. distance r s this function mean-square acoustic pressure, re D 4 c METHOD pute The prediction the far-field figure The i. general detailed The methodology noise. coordinate approach prediction for for A presented schematic system the each and prediction fan noise in of a reference typical directivity method component 8.1-4 1 fan angles is is is are presented. is discussed. used to shown in also com- shown. Then, the J The fan equation for the <p2>* = A'Hi 4_I(rs In far-field mean-square acoustic pressure for a is equation tion, (i), and tance rs H* S is the is expressed )2 is (i the D(@) S(_) - cos overall spectr,-in M (1) @)4 power, function. D The dimensionless is the source form to directivity observer funcdis- as (2) The (i forward - M velocity cos 0)4. effect The is accounted frequency for parameter by _ the is Doppler defined factor, as f (3) = where the (I - blade M cos passing @)f--b frequency fb is N*Bc (4) fb The = acoustic .L Equation (5) function F. constant G defined diA_e = power K _*_ G(i,j) contains The _he (si)-a(k' several constant depends for on the is [)Mb(m*/A*) m empirical K fan is noise expressed (.ST*) 2 constants as F (Mr,M m) and the noise (5) empirical different for each component and the indices i inlet inlet guide guide vanes) vanes) Dower component. and The j as i = (6) Ii (Fan (Fan with with no and j : (7) i (_ <> 1.05) 1.05) (5 8.1-5 / jr The fuandamental tone cut-off factor 6 is defined as M t (8) 11 where the fan rotor M t If M t > value of of the = tip number Mt is WN* t.9) 1.05, then 0 is less tip Mach Mach _ = than number M t. The fundamental 1.05. The cut-off where the fundamental tone factor cut-off occurs when the determines the range blade passing frequency dominates. The rotor-stator component and k _he spacing indices exponent k and a(k,£) £ depends defined on the noise as = (I0) i ('-* _> (s* i) i) and [ = (Ii) Ii (No (Inlet inlet Inlet flow distortion tends Inlet fl_w distortion is to reduce assumed flow flow rotor-stator to occur distortion) distortion) spacing during static effects. and ground roll o_eratlons. The design point :_ = max where Md is exponent b the in Mach n_unber index Mm is defined as (12) (I,._ d) design value equation (5) of gives the relative the tip effect of Mach [_m number. on each The fan noise component. The t&on general, point final F. _ Mach empirical _'_.e power _ _unc__on n_ber Mr quantity function of the indux. in depends relative .-h.e relative equation on tip (5) the fan Mach tip is noise number Mach number the power source Mr and is funcand is, the design defined in as (13) x 8.1-6 wherethe tip Machn_mber Mt is defined by equation {9) and flow to static Mach and number speed of As a the of The be The added to fan mean-square and polar falls ambient fan noise at is that pressure so determined. parameter band _ its is for a as band axial density own these functions computed given as set of I/3-octave-band frequencies. I/3-octave is has Using expressed the values. source angle discrete frequency inlet S. acoustic noise spectrum within the directivity values center the function the noise since to each spectrum appropriate i/3-octave-band that (I), and are the equal broadband tones m*/A* assumed equation power, i/3-octave-band number be frequency pure equal D parameters. must the can by acoustic data. is function function input sound indicated directivity and Mx The that a For a the lowest pure tones total given value of harmonic is n£ = [lO-1/2o n] + i and the highest harmonic (14) number is (15) nu = [lOI/2° n] where n% [ > are - + is tenes t_e directivit 7 the n to fan the Each observer functions pure is nu_.ber, -< nu, tone to to presband. data. the in in acoustic table tables discussed there appropriate compute in if then mean-square the summarized summzarized component n[ I/3-octave-band used are real If added as are enclosed The then components ncise the band. band. functions fan of the are and noise spectrum respectively. part within Dumber constants six and tone within propagated empirical for integer no harmonic are The i each tones the there n Z for ._ower indicates then nu sures The ] _u' II. III detail The and IV, as follows. inlet Inlet broadband turbulence random in Lhe unsteady vortices, sources The flow and of broadband noise flow _ne acoustic -" = are inlet broadband noise is passing (1.552 are due ( in beyond the to _he inlet 10 -4 ) (s*) "'_(k'/) scope is unsteadines_ of _he layers, predictions broadband 8.1-7 random Some boundary Although from _ower with blading. turbulence noise Noise associated the flow. radiated Broadband blade of of the this or sources of w_<es this and individual module, the total predicted. noise _ " M'(m'/A') m from the (_T*) inlet 2 F(M r) is (16) --'W l where the constant a(k,£) 4 is i (17) The exponent acoustic a inlet flow s > defined power i. by varies distortion The equation inversely effects power (17) with F for the rotor-stator dominate function accounts the fact spacing rotor-stator that the except spacing where effects at is F = (18) i (Mr -< 0.9) O. which is The plotted in (M r figure mean-square computed table SLMr2 from III and S = pressure (i). plotted in 0.116 The figure exu tion _ is the (19) is plotted 3. -0.5 geometr{c Discrete rotor or tone stator intersecting or by are the rotating from made to only the average The acoustic -" = determine (2.683 x is from from the the !0 -4 ) G(i,_) is given 3 is in given by equal to 2.2. Equa- Tones with are starer spinning to inlet lift vanes or stator duct rotor-stator (s')-a(k'[)M4"31(m*/A*) m rotor blades guide vanes inlet vanes. No each The attempt propagated tones is mode, predicted. interaction (iT') 9.i-8 on by modes. of are fluctuations generated on characteristics c_racteristics due is impinging as specific power is function and tones rotor blades far-field noise D (19) associated preceding a spectral Interaction Interaction wakes broadband 4. generation wakes propagated The Rotor-Stator blades. inlet function deviation figure Inlet to (n/2.5)_ in mean in due directJvity " where 0.9) 2. acoustic equation > 2 F(Mr,M tones m) i_= {20) where the constants are w • G(i, j} (21) O. 580 l = IO .625 1 0.205j and a(k,£) The constants vanes and spacing when in the matrix fundamental accounts inlet function (22) = for flow F G tone the account cut-off. inverse distortion for The variation effects the effect exlDonent of dominate of on the at the inlet acoustic s > 1. guide rotor-stator power The except power is -2.31 0. 397M (M r < 0.72) m F 2053C31, S --- (0 2 < r 0 .315M 3 "69M-8 m which is The action plotted given is a is in discrete III 0"462 (23) 0"462) < Mr) 5. pressure from and function 0.866Mm (0.866Mm acoustic computed table < r figure mean-square tones is in Mr plotted given due equation (i). in figure to inlet The 6. rotor-stator directivity The spectral interfunction D function S by n u s(n) = _ S(n,i, n=n where n Z associated value of and nu are with the I/3-octave _. For j) (24) Z n = the lower and band upper with a values center of t_e frequency harmonic number parameter I, (25; S(1,i,j) _0. 799 0. 387_ 8.1-9 and for n > I, S(n,i,j) = x I_i where i and function j are S(t]) is i/3-octave-band 250 i01 defined by plotted in Inlet The flow distortion interaction unsteady lift average The (26) equations figures (6) 7 to I0 and (7), prior to respectively. being The converted to data. Inlet stator I0 -0-3(n-2) 0"432 l 0. 307_ Flow has tones. on the properties acoustic an In blades effect the due broadband inlet produces far-field to Tones on addition, which of :_wer Distortion flow are (1.488 x rotorcan pure tone generate noise. predicted. distortion tones • •q* = and distortion additioi_al noise inlet noise fl,,w is 9 10 -4 ) (s*)-a(k,_)M4-31(m*/A*) (AT*)" (27) F(Mr,.Xt m) m -her,: a(k, 5) re_}_ectlvely, The and F(>Ir,M m) and the !xawer mean-_,_uare : _ computed from a:: for the •_lotted in acoustic equation inlet arc 6. The by F" is due The directivity to interaction sVectral equations plotted _ressure (i). rotor-starer figure defined function (22) in inlet and figure flow distortion function D tones as g'_ven in S is given by function 23), 5. is toner; the taDle same ITI and _U i0-" (28% / n=n w!_Ich iata. is "..'lotted _n 2 figure ii prior to Combination When tht, relat_v,: _eed value of I, shock waves _Icse ._hock waves _rouagate waves• The :n_tead ._f tonal but frequenc[.'. resultlng the e×tends This blade in are of a combination Noise rotor blade the Lhe contains frequency. frequency: engine ._olse inlet of as either often _.i-i0 a the resultant on is of l,'3-octave-band exceeds edge harmonics The to tiFs leading • interval tone converted Tone at through sFectrum passlng the formed beina side referred a each rotor series shaft of number blade. Mach speed no_se is of the to Mach as not purely harmonic "buzz-saw" I ! The acoustic H* The acoustic the They passing x 10 -4 1/4 mental K due to combination G(i,j)(m*IA*)(AT*) power computed. blade 6.225 " power for are three fundamental as noise of (29) the fractions tone. tone, The is r) shaft of the The constants K for fundamental combination combination combination F(M harmonics expressed frequency. for the I/8 2 tone and constant 2.525 G(i,j) rotational speed fundamental tone each harmoi_ic tone, 2.030 are x 10 -3 x 10-3 is for given the I/2 are of the for funda- b7 (._0) .316 This of accounts for combir_tion the 0.31 fact tones through that inlet the guide inlet. vanes The inhibit power the function propagation F is given by F(N r) = I0 -6"751!'61-Mr) (I -< H r -< 1.61) O (:% -1.21 the I.'S fundamental (1.61 combination < = i0-14" O -1.33 for the [/4 fundameatal 75 (i" 322-Mr (Mr-l. ) (i 322) combination "Mr < = O i0"31-85(i-146-M:} I I0-1"41 (Mr-l. < 8.1-11 t32) M r) and (I -" M r 146) I) 1.3..) (1.322 tone, - (_r F(M r) M r) tone, (M r F (M r) I) (Mr-l.61) i0 for < (31) < i ) -_ 1.146) (I. 146 < Mz) (33) for the 1/2 in figure The tone the acoustic b 7 tone. III and (i). The D plotted is Then, spectrum function table pressure equation I/3-octave-band directivity in combination mean-square combination yield fundamental power function is plotted 12. due is the in figure same computed the to for 13. three separately combination all The three for harmonics tone summed noise. The harmonics spectrum each are and function is S to given is given by S (n) = (34) -405(8D) 405(8D) for the 1/8 fundamental 5 -3 (D (n combination _> 0.125) tone, (35) s(n) for the 1/4 = I_ "520(4n)5 .520(4n) fundamental S([_) = _ combination the 1/2 fundamental combination tone tone, (36) noise "-3 combination are /lotted Discharge the noise The inlet tion discharge broadband broadband noise. tone. in The figure Broadband spectrum functions for 14. Noise noise is created The acoustic power by the same mechanisms as of the discharge broadband is _L where and 0"33212_13 _,O. 332(2n for -5 = (3.206 a(k,[) (17) and x is G(i 10 -4 ) the j) same _(i,j) as (s*) -a(k'£) for inlet (m*/A*)(_T*) broadband noise 2 F(M r) given by (37) e_aa- is (38) 8.1-12 The factor G acoustic power is by given shows of that the the presence discharge of inlet broadband guide noise. The vanes doubles power function t.he F (39) F (M r) and is plotted The is as and the plotted in (Mr -< i. 0) (Mr > 1.0) 15. acoustic equation is in The discharge power of _* qne as = matrix equation • discharge broadband function spectrum spectrum as D noise is function given in 643 x interaction rotor-stator 10 -4 ) is and Interaction give, in is the S equation (19) and the Tones tones are interacLion rotor-stator a(k,£) (21) to The Rotor-Stator inlet discharge (2 16. noise rotor-stator the the directivity 4. Discharge mechanisms due The figure broadband figure pressure (i). plotted inlet in 2 figure from III same i Mr mean-square computed table = created tones. interaction tones The Lhe same as for G(i,j) inlet the same is G(i,j)(s_)-a(k'i)M2(m*/A*)(AT') m matrix by acoustic 2 rotor-stator F(M r) tones (40) given by is (41) c,(_,j) = 2 which The gives power given in The the equation D functlon given is S in F (39) mean-square interaction tion effect ftLnction 0.58O] 0.820J .59 of inlet is the and guide same plotted in figure acoustic pressure is _uted from given in table is equations the same_ (24) as to the (26) and 8.1-13 due equation plotted inlet and and the tones III vanes as fundamental discharge cut-off. noise as 15. to discharge (I). in in The figure r_tor-stator plotted tone broadband rotor-stator directivity 17. The funcspect_ interaction figure_ 7 to tones i0. "_ as Output Computation The sun of user has nents the option of mean-square The by the output pressures acoustic from deleting one the or pressure six more fan of for noise the noise a fan is the components. source The compo- desired. frequency, angle. mean-square mean-square the if The of I/3-octave-band the total acoustic pressure polar directivity noise is number of engines is available of the is angle, computed and mean-square for azimuthal acoustic Ne for the output table. the sound pressure level SPL each desired value directivity pressure multiplied In addition, defined as printed _®c_ SPL and d_e power = i0 level lOgl0 PWL /_kp22 * + 20 defined lOgl0 (42) -Pref as 0c_A*A e (43) PWL = I0 lOgl0 _* + I0 logic _ref REFERENCE I. Hei!mann, __ource M. F.: Noise. Interim NASA TM Prediction X-71763, Method 1975. 8.1-14 for Fan and Compressor m TABLE I.- RANGE AND Input parameter Minimum 2 Ae , m N e m A _ d [ • o . . . . 1 ° ° ° . i00 i0 20 i00 I.!28 1 " ° ° " ° ° " 1 1.0 ...... i , kg/m 3 ..... 2 2.0 1 2 1 I0 i0 50 200 ° 0 0.2 i0 ° 0 ........ m/s 4 0.2 o ......... ....... 4 2 0.5 . Max imttm I0 _,14 1 . "T* De fault 1 ° ........ "_,1o IN-PUT PAR/LMETERS 0.i ......... ._1" C a, . 0.3 . S* ".7 . ........ Md OF 0.01 ....... .... VALUES 1 i .... _ 1 0.01 ...... ........ r S , DEFAULT 0 0.9 0 0.3 0.5 0 0.2 1.3 200 340.294 4OO 0.2 1.225 1.5 8.1-15 _D c_ vI V A Vl "J" vt Z X VI A VI _. V! Vl _. v v ° t i L. E o _, , T O A A 0 _ C r2-'D _ A &_; IO tc t 'll x I",I _n u_ ,4 0 C j 8.1-13 "J _ _P _-_ V le X I-4 ,..4 ,,.4 Vl A 0 0 ,-4 _" Vl A X Vl V! A A _ l.J Z I., _r le Z Z 1E X V! V! p-0 k_ v r._ 5" ! _D I _t f-J Ii.I ,-q w v X v a0 I 1 t O O O 0 O ol ! "_O O t. r_ ,:; o I A A o w v A _ v v • 6- 2_.2 ! O I O _0 x x ,.,..I v O O 0 '_ e 0 ,,, _ 8 _, I 8.1-17 rU O_ _., 0 _a2_ r r. o 0 >, o.,-_ o .i.J _ _ eJ o _J 1.4 _ ,.4 t2 _ .,.4 .,.¢ 01_ o ,...4 0_ o O O_ I I 0 I I I 0 e 0 O_ I I I I I I O 0 0 0 0 i|il 0 O O O i I I I I I I I I I o O0 I I eU >, oooooooooooooo_ooo 0 Z _,_ I I I o O0 l I I o c 0 Z < t,. >_ 0 g_ o3 e" .,.4 Ol ,-4 14 l 0 _ o_ _ o_ e o o 00000000 I I o • o • e_ I I I t I o_ I 0 0 0 ,-4 C _ 0 _ 0 > 0 ,--4 0"_ I I I I I I I I l I I I I I I I I I I I I I I I I m >. .,-Q -,'_ ¢) 0 • 0 0-_ ooo 0 • • • g gggg ggg gg g ___0__ 8.1-18 _ TABLE IV.- SPECTRUM FUNCTIONS Source FOR Spectrum broadband S(q) noise = 0.116 inlet exp L 0.5 NOISE function r_ Inlet FAN ,hi2 ,,]q L In 2"_'.2 J J n u rotor- stator interaction S(q) = tones I S(n,i,j) n=n Z whece S(l,i,j) -0.499 0.136 0.799 0.387 = %.2s0 S(n,i,9) x 2.1oi Inlet flow i0 -0.3 (n-2) (n > i) o.3o L n u distortion S (n) tones 0.43! = = 9 I i0 -n n=n & 1/8 funda- mental combination tone s(n) = _ "°'4°5 (8n) 5 [.0.405 (sn) -3 noise 8.1-19 (_ ! 0.125) (D > 0.125) i TABLE IV.- Concluded t Source Spectrum function F 1/4 fundaS(q) mental 520 combination tone 1/2 -< 0.25) (4rl) -5 (q > 0.25) noise fundas(q) mental = 0.332(2n) Lo 332(2q) (n < 0.5) (rl > 0.5) 3 combination tone (rl = -3 noise Discharge broadband noise s(q) = Discharge 0.116 exp L°'5L in 2.2 j j n u rotor-stator interaction s(n) S(n,i,j) = tones n=n_ where S(l,i,j) = 0"1361 0.387J S(n,i,j) = 0"4321 0. 307_ 8.1-20 × i0-0.3 (n-2) (n> i) N / r / Figure i.- Schematic diagram 8.1-21 of typical axial flow fan. 1 _7 t / 7 / / / / -- -Q o £ = C) Z c o = .,.., o I i= > Q) °_ c_ I t T l I, I 1 _ , f o 0 i °_6oI ,r-- ,r'-- i f 'la^a7 C_ t JaMO d 3.1-22 i _) I J 0 o OC i ' o t o / / / 0 i 0 / < o o-- > o-- > °_ N o ! 0 0 0 I 0 C_ L_i i I 1 i } I I 1 I { { (3 °'6oi 'l_^_'] f'}!A.q.O_J!O 8.1-23 o I 0 c# 0 C /J m 0 0 0 _ CY_ 0 / m _" C C12 ,_ _ U o i_ "'_ cr 2 > 0 i.I I ° 3 0 0 I S °tBOl "laAaq _n_0_d S 9o 1-24 I 0 _J 0 / < o E o r_ o o 0 ( \ \ \ S \ ,\\ o_ I--- = o t / ql /, I" / / if2 o 1 v" 1 1 l ,1 1 0 t '¢') l l J _ 0 uO I -I °=6ol 0 M I I 'I_^_'IJeMOd ; I I I I O 0o / / o (.0 111 0 0 11 o 0 --4 .,I,J U mr-'-- ¢) ¢) ¢D 0 r', -,,-,I / / _ 0 0 e- C) --io 0-- C / J / < I 00 P / > o__ J I / °_ J ___c ,¢.D / / 0 i __io >. I3_ ! O'4 .,-4 1 O I "I 0 °_5Ol 1 1 I _ I if3 I ',m'I 'I_A_-I XI!A.qO_J!C] 8.1-26 I LI3 I Io _,0 I --! _0 t- O tO _d •= > e. ¢ 0 _ •tJ OJ I c- 0 O 0 6 0 _ _ 0 U m _ _ 0 r_ o c- 0 e- l I,... •_ 0 0 I t" -,4 _ _) 0 _'_ '0 0 E E U _ C_ u I I 1 I 0 ,z I "-" I _ I r'O "I I o S °L6Ol 'I_A8-I _n_o_d 8.1-27 S / 0 0 4.1 4J r" 0 0 .,-I 0 I 0 ETI 0 0 0 '_ 0._ 0 I -.-,I .m 0 rY (j c- r" U ,_ ,.t.,_ tL.= 0 I O" =_ U t- LL 0 _ E m C r" I I •-- I 0 I _-- I 04 I S °t6Ol I 'le^e'l uJn_,oeds 8.i-28 ix') I I _2 _0 0 aJ 0 -,.4 Lr) '0 }.4 .,-I 0 •_ O_ m ! 0 ,.-4 0 4_ -t,'4 o,.c 0 _'_ e_ 0 rY "'_ O .,_ I 4J o c oq) e" b_ _ C 0 I O E _ E _7 O e- ) ! I •-- J 0 l I u3 "-- (x4 .3"-- I I S °LOol 'le^e9 cun_oed_ 8.1-29 I I 0 C 0 C O e-, ,G 0 o _ m o 0.,.4 0 e_ 0 rr u m .,.J t,4 o o E _ o i _ r- u _ o t_ o E 1.1_ _ E i iJ c _ ,..,4 u_ 0 I 'l_^e'l C_ I uJn_oadS 8.1-30 i .,.., 0 v-- L_ ¢: 0 .4,J 0 c 0 _J 0 0 o d n,o t- I o.- --'4 0 0 i, U 0 ! I --2 I 0 I I "-- _ I S °L6Ol 'le^e"l I uJnAoed 8.1-31 S l _. _)-- I I J// O.J "-" 0 0 O'b ..- i i I I I 0 ur) ,,e-- I 1 ! 0 0 I °_6Ol 1 u_ 1 'le^e-I I 0 I 1 _ I JeMOcl 8.1-32 0 I I ! 0 JJ ..a o ('0 0 _ o :'; o ._o..; I--- > n," _ :2 0 moo 0 0 o c" ¢1 t-, 0 o o "41 aJ 0 ,ql-- E o U t_ 0 / e_ > _D > _D / / I o U e_ C3 I CN I I I I I I I I I I I G °LSOl 'le^e-I 8.1o33 XI!A_OeJ!G I m 0 0 0 0 t-U .,-4 o" 0 £ ! J E U ! 1,4 -2 0 _ I 04 I t.") "-I I S eL601 'l_^e'lwn_o_ds 8.1-34 m 0 o 0 _ C _0 U _ u I Q. '_ 11o 0 t_ I f I :2 j I 1 1 I 0 0 I 3 °_8Ol "1_^_"i 8.1-35 I .J_Mod 1 I I 0 I ._ / 0 / 0 n / qr-- 0 U) 0 t° O_ L, E u > U > ._ m \ > c \ \ 0 ,<- MO I 0 1 i i "-- >. 0 I I I CI °L5ol '{_^a-i ,_},!^._o_._!C! 8.1-36 I o I _ .,,4 r, ! 0 / -I° ¢0 O0 cO i -i° 0 ffl 0 o ,IJ ! 0 0 o 4O 0 t< 0 e" CO > ___0 L,_ °_ 0 C3 _0 L. 0 11 G .,,..i ,j I 0 (.'_i I t_ I I 0 I "-" I I C_ I _ I a °L6Ol 'Ig^e'l 8.1-37 _I ,_1!^.q0eJ!Cl 1 if3 _.D I I o .f..t e,. T i 8.2 COMBUSTION NOISE MODULE INTRODUCTION The Combustion bustors Noise Module predicts in gas turbine engines. by R. K. of core installed posed appendix empirical data engines to produce directivity The and Parameters sound are of acoustic SAE ARP as a from method 876. The turboshaft, spectra requires exit the or azimuthal not to the output vary directly conventional is based method of on and as with by The a the provided user. is of angle. parameters. be The function azimuthal is several module and executed output polar other a for table polar it noise is combustor Core Noise user-provided of each set the noise combustor Ae engine ca ambient D directivity f frequency, fp spectrum peak frequency, H aircraft Mach number & mass N number <_2>* mean-square total P= ambient area, reference speed angle, is introduced area, of m2 m- sound, (ft 2) (ft 2) m/s (ft/s) Hz of rate, kg/s Hz (slugs/s) engines acoustic pressure, pressure, pressure, pressure, Pa 2 x re 10 -5 (Ib/ft2) Pa 8.2-1 (Ib/ft 2) Pa 2 4 O_c_ (4.177 × 10 -7 ib/ft assumed so tables. function flow reference Pt entrance of mean-square directivity combustion angle, with the once is frequency, directivity compatible The by Additional Although A f pro- turbofan frequency SYMBOLS Pre coma employs turbojet, function can parameters. directivity table of parameters required. input pressure and input flow Module parameters values to from noise The angle. method entrance Matta noise the 2) _at _ distance r from source to observer, m (ft) s t dimensionless r distance from source to _bserver, re _e s S spectral T total ATde distribution temperature, design s function K turbine ambient (OR) temperature temperature, 8 polar II* acoustic _ref reference K directivity O C3Ae 1 x 10 "12 density, azimuthal kg/m 3 directivity (OR) deg re power, K (OR) angle, power, ambient extraction, W (7.376 (slugs/ft angle, x 10 -13 ft-lb/s) 3) deg Subscripts: i entrance j exit Superscript: * dimensionless quantity INPUT The the combustor output of conditions The are frequency, arrays values A Ae N the and of exit parameters Noise Parameters required for computation polar the engine distance _he and Core establish Finally, area, entrance Lhe directivity angle, independent variable reference to input combustor parameters entrance engine reference number of distance area, observer or of s_und the and number of required. are given in Input Constants area, re m2 for source to the The table Ae (ft 2) observer, r S 8.2-2 m (ft) either Ambient levels. directivity the range I. from user. pressure enqines, engines from required from azi=_thal values are area, are .Module output angle table. combustor and default entrance j_ Core L Pt, i T" J A T* des Noise combustor entrance mass eombustor entrance total pressure, combustor entrance total temperature, combustor exit design total turbine flow ambient temperature sl_-ed aircraft of Math ambient mnthal [uovlded out_,ut as a sound, kg/m dtrectivtty m/s ] for module of angle. the from frequ,,ncy, polar anqh,, is _n • T_ re Tm ]) Arrays deq PUT a table of _olar addition, the mean-square, direct_vi_y the observer angle, distance .Module. source to observer, Norse m [ft) Table H: dir_,ctivity azlmutha| h T deq Combustor f re (ft,'s} Variable frequency, Proi_ation distance r_ this function directivity Poe re (sluqs/ft anqLe, dir,,ctivtty of r_ Ae Conditions OUT The c Hz a;'.tmuthal |_ressure D extraction, Ind,5_ndent }k)L,lr re number density, t'requt,ncy, rate, temperature, Ambient MoQ Parameters anqleo dirt, ctivity ,|eq anqle, deq O me.xll-_uare aCOUStiC Vressure, 2 4 r_, ,_ Cp acoustic and rs a:iis .METHOD The _e prediction combustor method are shown in methodology noise. given in figure proposed Details reference I. The of the i. A coordinate by R. K..Matta development and schematic system of and a is used validation typical to compute of the combustor directivity angles is are also shown. The equation I/3-octave for band for <p2> t a = the far-field gas turbine ntA * mean-square D(_) 4_(r:) 2 (i - acoustic combustor pressure in a is S(f) M (I) cos @)4 Q The dimensionless The acoustic states source power to ]* observer is distance related to the is combustor defined as entrance and exit as -* * &'/T"T[ me rs aircraft Mach number term in ")2 (3) >2 "'" equation (i) accounts for forward for equation (I). flight effects. Two t:vity empirical functions f'_nction is given 1& a in table function figure 3. D f The engines N. acoustic pressure and of azimuthal the sound The the as of a ?ressure 2. given The in given The spectrum table direc- angle 0 function Ill and plotted and S in by (4) <?2>* i_ now pressure this module of angle. level is is directivity 9 function d_rec_ivlty polaz figure and mean-square output the in fP pressure _s of (f/fp) 400 M,_ cos 1 - required plotted frequency = noise are function and mean-square total a logl0 _ak P =_.e II of The is a from by table frequency, In SPL is computed multiplied polar addition, defined of printed the equation the (I). number of mean-square directivity outFut angle, is available as 2 ,3 _P:.. 10 1ogi_ <p2>" = + :0 l°gl0 C _ " Pref 8.2-4 (5) f and the power PWL level = 10 PWL defined lOgl0 H" + as I0 (6J logl0 REFERENCE I. Emmerlinq, Control d. FAA-RD-74-125, AD A030 J.; Program. Kozin, S. Volume III-I, B.; Ill, Mar. 376.) _.2-% and Matta, Supplement 1976. R. 1 (Available K.: - Core Prediction from DTIC Engine Noise Methods. as TABLE I.- RANGE ANDDEFAULT VALUES OFINPUTPARAMETERS Input parameter A t . . Ae , m 2 N o o o . Minimum . . ...... Default 0.01 1 i0 0.01 ,_/4 I0 1 4 1 ........ 0.01 rSS m i00 ....... m*. i ° '%_oo ........ P:,i ° ° .... • T* ........ . ° o 0.2 0 o i0 0 0 0.9 1 i 30.0 1 1 5.0 1 2 6.0 ....... T. _ 1 Maximum .... 3 '_Tde s Coo, 0 ....... m/S 340. 2OO ...... 0.2 _ , kg/m 3 ..... [ 8.2-6 0.5 2.0 294 4OO 1.225 1.5 "----"I > UI [.., U M 0 0 ,...4 I | I I i I o * • • • • I i I I I I i i I I i I i I i I i I i I i Z Q en 0 U ! 0 _00000000000000 I I I I i * * * • I I i I I i 000 | i i I o o * o . o_ • . 0000__ I 0 Ul e_ o ,-.4 0 000 I I I I I 0 Z © OOOOOOOOOOOOO0_oOo0 0000000000000000000 i ).., 8.2-7 0 v I O0 i i 0 I o . . o . o . ._ i J J j ° ooo c_ o o oo c_ooo X Z Figure I.- Schematic diagram of typical 8.2-8 gas turbine combustor. I ¢D 1 '¢ l e_l I 0 I C,,I I G °tSOl 1 1 ¢0 aO I I I X_,!^_0eJ!CI 8.2-9 0 '¢ 0 I wO 0 Q. '-_ 0 o uu3 0 o" °m 0 0 ...4 o 0 0 I l I I I Cx; M') ,_- I I I I S °tSOl 'l_Aeq wn4o_d l LD I _ I i S 8.2-10 L. _j I I •-- o b_ m 0 (j ;',."-- I I -7 8.3 TURBINE NOISE .w_DULE INTRODUCTIO_ The Turbine for an axial the General functions to a pure The met_hod and Parameters to vary output or pressure azimuthal with table I). based The as a is input of noise on a method function the s,-- directly can by The a a the of angle. fxequency is with executed output engine a,b components B number c=0 ambient D directivity d turbine f frequency, fb blade inlet other a polar it is for table turbine noise cross-sectional reference of area, rotor speed polar compo- area, m2 m 2 (ft 2) sound, m/s (ft/s) function diameter, m (ft) Hz passing frequency, }:z ratio h" specific enthalpy, re ha absolute htunidity, percent K constant 8.3-1 RT mole fraction turbine Turbine of each the directivity noise introduced tables. blades of rotor fuel-to-air by .Noise user-provided once is frequency, angle, the SYMBOl3 A e and noise The by Additional Although directivity compatible turbine tones empirical broadband provided user. The function azimuthal A pure developed employs of of and method parameters. be module parameters. as several parameters directivity is broadband is component. flow input (ref. spectra required. the the method spectrum requires are of acoustic tone exit 7 sound Each Module parameters values and produce and predicts The Compan angle. entrance Module turbine. Electric directivity nent Noise flow (ft 2) is set of mean-square angle, assumed so that not the aircraft Mach number _m H rotational number speed, of Hz engines e n tone <p2> mean-square Pref r s r t S harmonic acoustic reference pressure, pressure, distance from 2 source dimensionless distance gas m2/(K-s constant, S sp_ctr,_ T temperature, blade n number I0 -5 to Pa (4.177 observer, from 2) m source K tip speed, ambient power, power, densitq_, azimuthal exit s static t total m/s • re _e (ft/s) angle, re 1 deg D c3A × 10 -12 W (7.376 kg/m directivity 3 (slugs/ft angle, 3) deg ambient Su_Terscri.:t observer, (ft2/(°R-s2)) : 3 2} parameter reference entrance ib/ft (ft) to 'ref i i0 -7 (OR) directivity acoustic Su=scripts x function frequenc/ polar x 2 4 D_c re : dimensionless quantity 8.3-2 x 10 -13 ft-lb/s) INPUT The Turbine turbine Parameters for :omputation required directivity pendent angle, variable sectional area description of of and engines, default parameters Noise values are of and or for and number the turbine. pressure the output to input rotor the engine reference number of The are area, given in (ft 2) e H e r s distance engines from source to observer, Turbine A • turbine B number dj turbine inlet of rotor rotor fuel-to-alr N* °s,j exit diameter, re Turbine _ise total re c _z _A_A_ Parameters temperature, re tem--_erature, speed of absolute humidi_/, aircraft Mach ambient re /d re Ambient M area, blades speed, static ambient (ft) ratio rotational entrance m Geometry cross-sectional density, T T Conditions sound, m/s percent (ft/s) mole fraction number kg/m 3 8.3-3 (slugs/ft for required. 3) Ae the inlet reference Constants m2 frequency, turbine requ/red engine of the inde- geometric range I. are polar cross- area, The table the conditions establish The are parameters output levels. are the observer the Ambient arrays blades Input A either user. table. Finally, distance the directivity the of from from sound azimuthal values of required MJ_dule number and IndependentVariable frequency, polar Arrays Hz directivity azimuthal angle, directivity deg angle, deg OUTPUT The output pressure as muthal provided to a this directivity for the of from is a In frequency, 0 polar source to the mean-square directivity the observer, observer m Noise acoustic angle, and distance azi- rs is (ft) Table Hz directivity azimuthal <p2_f,e,¢l>" of polar addition, Module. Turbine f table frequency, angle. Propagation distance r s module function angle, directivity mean-square deg angle, deg acoustic pressure, re 2 pc 4 METHOD The prediction the far-field ure I. The general tation method noise. coerdinate equations is turbine A system for followed noise the by a <p2>* for equation r and is and a reference typical method discussion i is used turbine directlvity prediction detailed = the (i), S expressed is far-field _*A* 4_(rs tion, in of is angles are of are presented. the to compute shown also in This method fig- shown. for The presen- each component. The equation turb!x,c is In presented schematic _" the in )2 is (i the spectrum dimensionless mean-square D(9) ._;(_) - cos M overall pressure for a (I} @)4 power, function. form acoustic The D is the source to directivity observer funcdistance as s r::rs/ e (2) 8.3-4 Theforward velocity (i 0) 4 . - _ cos rl = where the effect The (1 - blade is accounted frequency M cos passing for parameter by q the is Doppler defined factor as (3) _q]_-b frequency fb is (4] The acoustic power _* = K t,i \ The constants particular the s,j turbine [[* is expressed as (S) (u_)b ht,i K, noise entrance for a, and source sI_-cific b are being total determined from considered. enthalpy h;, The i and empirical difference the exit of the data of between specific the the static * e:,thal_y cific hs, %. enthalpy is the idea[ is computed ratio ,%, and the ?roi_:rties Utility. absohlte The rot.,tional speed 11T A_ = _N tions and puted as the d.lta. tones must by added the number to turbine falls the with U: spe- fuel-to-air the appropriate is a functlon turbine polar Th_ e broadband are the values apFropriate noise spectrum within frequency the band noise function mean-square and center n. - [I0 "lz° each spectrum frequency tones i/3-octave-band that (1), and power, of [_ure h/3-octave-band of D }_arameters. be ha s|_eed Each the of Gas the by equation acoustic The turbine. temperatures, _6) function in_,ut band input humidity rotor tip i:; given function a extraction • iudic:ited dir,,ctivity :;et of and _rk fro.'.* the S. acoustic directivity noise at is I/3-octave ._ts these pressure angle as band so For n, the a comgiven I/I-octaveT_e that a own func- is for frequencies. determined. param_tez has using expressed discrete is ,_ource By a g_ven lowest pure to_al value harmonic is n] + I (7} L anJ th,, highest harmonic = n [ 101/20 number is ".] (,g} U S.3-5 whrre [ :I[ _ nu, are nu sures The ] indicates then - n£ for The l are |:ropagated empirical noise the number n the are com_x_nent given is tables described Turbine broadband random, iu in and noise noise The flow ,_re III acoustic the the due }_owor to to II. The there pres- appropriate band. data. compute the acoustic directivity following with and s_ec- Each two random Some boundlry of is If then mean-square the respectively. o_ turbine sections. unsteadiness the of this blade of this wakes and individual module, o_" sources layers, prediction sconce number. -< n u, Noise in turbine tone to used blading. Although n& i/3-octave-band the associated the pure IV, in turbulence beyond by and detail is flow. is produced table real If added as Broadband |_assing entrance broadband band noise flow unsteady vortices, of the The functions in enclosed band. then observer Turbine turbuh'ncc band. given in the the are and are of within within to noise part tones constants turbine functions inteqe.r no tones harmonic for trum + are each tones _owor the there the sources total broad- predicted. broadband noise from the turbine is ,,e {S.SS'_ _,, dir,,ctivity ur,- 2. Th,, '.'i,lure 3. ,',lu.,t_ou _ 10 -5 ) function _l-,-ctr_rn Th,' D ' is function moan-::qu.lr_, given S harmonic:_ fief,! tone starer of gen,,ration bl.%des. the turbine c!l._r.lcterist_c:; The (9) {UT )-1"27 table ,liw, u Ill and iI_ table _re:;:_t:re plotted IV i:_ thet_ and in plotted computed figin by (1). D_::crete or " in is acou.qttc T11rbine tutor" • i hi, i acou:_tic Pure is tones blade },ass_nq _.ow,,r due _I.162 _ with occur at lift fluctuations frequencies frequency. The that average _,r,,d_cted. to turbin,, "t,_ [_* = Noise associated These are Tone F:U:," tone no_sd -h:,% lO'"_ (U_) -4"02 <_ ,, )I .46 h:, i _.3-6 is on are far- _,e directivity ure 4. The S which is computed function function - _ 0.6838 plotted bv O spectrum in given S The _lar is 5. acoustic It direct_v%ty the for the _ound the The mean-square output = and plotted in fig- acot,stic pressure is ".hen and for for each a:imuthal In level SPL loqh_ <p22" 20 value of an_le. by printed defined i:; the turbine multiplied addition, ÷ a des_r,,d directivity pressure table. I0 Computation pressure computed acoustic pressure SPL is angle, mean-:_quare Ne ZlZ by (I). mean-square components. table given (ll) Output two in is lO "(n-I)/2 figure equation is the output sum the The numb_-r is of t_.e fL-eque._y, t_ta] of noise er_::nes ava[|_Lb|e ;f as (12) log|0}_re f and the _k_w,,t" l,,vel I'WL defined ,is e PWL - lOqlo I0 :: ÷ 10 lOql0 .? 'ref _WE_ENCE i. Matt.%, R. K.; _:%v,'._tiqation (Avai|able ._andusky, from Low DTIC G. ?. ; al_d Emi:-sion as AD S.3-7 ."k_yle, _::%qit%es. A04S 5g0.) V. L. : FAA-KD-.'7-4, .:F, Cot,, Feb. .v.n_%t%_, _k-:_e t._77. TABLE I.- RANGE AND Input pa tame te r ° Ne . . . . I0O 0 0 0.9 , 0 0 o • 0 O. 3 ° • 0.5 3 6 0.5 2 4 ° • ° ° ° ° o o . d4 o o • ° . ° . • •%_ . ° ° o ° ° o . o . . ° o ° . ° . • • • • T t ° • . . ° T_, j ....... 0.I 2 , 0.01 I00 ...... If.- CONSTANTS Source FOR 0.5 400 0 4 1.225 O. 2 _' , kq m 3 ..... 0.06767 340.2')4 0 ....... TABL/_ 4 I oO ° % I I ° !I.%, I0 500 o g%,' ._ n14 20 ° , Maximum I0 ° C De fault i o t,i PARAMETERS 0.01 ° _t INPUT I ra ....... t_ e OF 0.01 0 ........ i rs, VALUES M inimum m2 Ace DEFAULT TURBINE ACOUSTIC a K 1.5 POWER b Bro,hlb,_nd ,q, 5,q9 _ 10-5 1.27 -1.27 Pure 1 162 1.46 -4.02 tone _ 10-4 _3.3-8 TABLE III.- TUP,_INE NOISE DIRECTIVITY Tone Broadband directivity deg directivity level, level, lOglo LEVELS loglo D D i -0,789 "0.689 -0,59g -0.509 -0,_09 -0.319 -0o219 -0,1Z9 -O*OZ9 0,071 0.151 O. ZZ1 0.Z31 0.Zll 0.111 -0.029 -0.229 -0.549 -0,869 . 10. 20. 30. 40. 50. 60. 70. 80. qO, 100. 110. 120. 130. 140. 150. 160, 170. leO. TABLE ',V.- TURBINE lOglo -O.Q03 -0,796 -O*bgg -0.602 -O._OZ -O*3qB -0.301 -O.Z01 "0.097 0.000 0.097 0.204 0.301 0.60Z 'l BROADI_AND -1.911 -1.671 -1.471 -1.Z61 -1.061 -0.851 -0.641 -0.431 -0,Z31 -0.021 0.189 0,38g 0.589 0.259 -0.191 -0._91 -0.931 -1,271 -I,611 NOISE logl0 -1,884 -1.604 -1.444 -1.304 -1.184 -1,084 -1.004 -o.gz4 -0.844 -0.784 -1_004 -1.204 -1.384 -l.gZ4 ._PECTRU._I S -----m X Y Figure i.- Schematic diagram of typical 8.3-I0 axial flow turbine. .J J O O O 0 W O L z_ •_ o O O 0 0 CO __ °_ ,_ .L a >, _ 0 o u _ __ 0 ! _4 1 __ I I I I ' I I I CI°'601 'l_^eqX_,!A.rl0ej!( ] 8.3-11 0 uO o I 0 0 r- .Q 0 0 0 e_ 0 r_ o ca) I cr 0 > L-E i (J 2-. ! 0 _a l I o S UL601 I I I I '10A_)7 wnzl°eds 8.3-12 0 t- f_ >,. 0 u 0 m o Q_ I 0 0 [ { { 0 I I I I CI °LSoI 'le^_7 X;!J'..r',.0eJ!O 8.3-13 l 0 m m 00 e e r. •- 0 0 0 0 u _ 3 > _ h _ I { I I I .,,=I o cO I I "-- I 0 I [ _" C4 I I S °L6°l 'l_^e7 wn.,'_o_ds 8.3-14 i 0 I I I / 8.4 SINGLE STREAM CIRCULAR JET NOISE MODULE INTRODUCTION The stream based lated as a Single jet on SAEARP in terms function The flow 876 of of method by module eters. function angle. and once a frequency, of employs the each set the Noise of noise so assumed that engine fully _j reference area, expanded ambient jet speed D directivity --4 fully F spectral f frequency, of m 2 area, sound, (ft 2) m2 m/s jet diameter, distribution m factor Hz t _ Helmholtz number, aircraft number ? <p2> power ° Mach of f A_e/C _ number velocity index engines deviation mean-square (ft/s) function expanded forward (ft 2) factor acoustic pressure, 8.4-I (ft) is tabu- sound The spectra nozzle values of the acoustic and not the to required. input param- pressure vary or are azimuthal output exit Module parameters angle, is introduced produce Parameters mean-square directivity method data angle. parameters. Jet SYMBOLS A e to single The empirical groups several the nozzles. user-provided of exhaust angle, it is noise tibles. predicts directivity by for table polar jet method polar Additional is Module circular dimensionless provided executed Noise The input be user. Although directivity with other relevant requires the Jet shock-free 1). frequency output of from (ref. can is The Circular noise parameters directly The Stream mixing with table as a directivity azimuthal is compatible reference pressure, 2 x 10 -5 Pa (4.177 x 10 -7 m (ft) Ib/ft 2) Pre f distance rs from nozzle exit rs dimensionless S corrected Strouhal jet temperature, C Tj V_ distance total to observer, from nozzle number, ambient temperature, exhaust jet to observer, re _e fdj/_Vj K K exit (OR) [°R) veiocity, m/s (ft/s) J If* angle between polar directivity acoustic power, re power, density, 1 kg/m density, azimuthal c_Aj × 10 -12 3 directivity density W (slugs/ft kg/m engine inlet axis, deg factor 0 3 and deg correction ambient 0 angle, number jet O. 3 vector Strouhal reference _ref flight (7.376 x 10 -13 ft-lb/s) 3) (slugs/ft angle, 3) deg exponent Superscript: dimensionless quantity INPUT The .Noise 3et parameters Parameters computation quencf, of polar establish dne distance val_es the of number angle, variable area, _nd N engine reference are number of area, azimuthal of for engines, required. given Input A e sound values are parameters either Ambient and number p:eudo-observer input from user. independent the _ne the Strouhal reference to required or directivity _ne engine are .Module in Constants m2 (ft 2) engines 8.4-2 the output conditions pressure output engine The table axis range I. the Jet required levels. directivity the of are The angle table. arrays Finally, offset, and for fre- default and ! distance r from nozzle exit to flight vector pseudo-observer, m (it) s angle between Jet A: area of jet, re and Noise engine inlet axis, deg Parameters A e J J v: ] jet total temperature, jet velocity, jet density, re re T c t _j re O_ Ambient speed _cp M of sound, aircraft M_ch denslty, kg/m m/s Conditions (it/s) number 3 (slugs/it 3) Independent frequency, polar Arrays Hz directivity azimuthal Vari-=b!e angle, directivity deg angle, deg OUT;L_ _ne a func=ion output of tivlty angle. the Propagation r s of this In addition, Module. distance frcm frequency, polar a table directivity of nozzle exit Stream to the mean-square angle, pseudo-obse.--ver and distance pseudo-observer, Circular Jet Noise angle, directlvity mean-square angle, acoustic pressure, re _.4-3 is m Table deg deg 02c 4 _ pressure azimuthal rs Hz direc:_vlty azimuthal is polar Single f module frequency, as direcprovided (it) for METHOD pute The prediction the far-field shown in shown. is figure methodology The The coordinate empirical except for equation i/3-octave A I. Whenever used, for <p2>* = In equation tion, (i), and F functions expressed The which r: = is D(e,v;) V*3 The ratio (6.67 and nozzle com- angles are the last extrapolation, is also value extrapolated. acoustic pressure in a is overall (I) power, D distribution is is the directivity function. The observer Each distance func- of these rs is as is the classic 13). P civen in is The II It (3) of the the such in D is V; of of function 2. in equation @ the III (I) and power from table are of The power angle variation functions a figure acoustic lOgl0 directivity expresses empirical _ plotted function polar Two exponent of function directivity normalized law. and deviation a the V8 density table the as of by 10-5)_jjt -*'_''(vj)*'8P'V*"j) given Vj. is Jq_ of is expressed in figure 3. lOgl0 to jet F(Sc,e separately. form x equation function 9 directivity used (2) normalized empirical is ,V;,T;) the power factor It with = and 1 exhaust rs/_e variation for deviation law. plotted a and mean-square jet spectral discussed dimensionless reference typical linearly ) is the acoustic required logl0 _* is is in _* far-field _q*A; a require are stationary 4n(rs2 in of system which the a schematic functions spectra for band presented noise. the V8 and is an velocity mean-square pressure that T D(9,Vj) The directivity table IV The t_zon of and sin function plotted normalized corrected velocity ratio Strouhal number in @ for figure spectral Strouhal d6 a = (4) 1 single stream distribution number log.^ V*, and iu 3 S c is defined circular jet is given in 4. lOgl0 temperature factor S c, polar ratio as 8.4-4 F is an empirical directivity T_. The angle corrected func@, (5) wherethe jet diameter d_ is (6) and _ is the correction V* 3 5. l°gl0 figure s,lch Strouhal factor and the The that the ntLmber is an correction empirical polar directivity normalized angle spectral sun,nation over factor. function The of the 8 as distribution i/3-octave-band Strouhal velocity shown in factor F Strouhal number ratio table V is defined numbers and is (7) F(Sc,_, _ V*j,TjJ -*" 1 = S c and is given in Equation fcrward table (i) flight exponent 7 as flight vector taken must n-_--ub e r and valid is from and the be taken plotted for a equation = 47(rs)2 m(@) figure veiocity is effects, <F > The VI in figure stationary (i) 6. 3:t should (M be x - _= cos (_ - 5) the forward reference velocity 2, engine inlet into account and axis. by is In 0). To incorporate as \/v*j index _ = rewritten (8) given _he angle addition, computing in the the table VII between relative corrected and the jet Strouhal as (9) Sc = [(v_ - :_) The value _ngle. _ne mean-square of _e The number output is level SPL acoustic frequency, total of noise engines available defined pressure polar is N of the directivity the for mean-square _ne output mean-square as 8.4-5 can be computed angle, acoustic table. pressure for and each azimuthal pressure In addition, <p2>', sound desired directivity multiplie_ printed pressure by 2 4 0_c=o SPL = lO iO91o<p_>* + zo I_io and the power level PWL defined {I0) 2 Pref as _ref (II) P_V_ = i0 lOgl0 N" - I0 lOgl0 3A*A _c j e REFERENCES i. Gas Turbine Eng., 2. Hoch, R. Studies _TE Jet Mar. G.; of paper Breathing Exhaust Noise Prediction. ARP 876, J.; and Soc. _tomot. 1978. Duponchel, the presented Engines J. Influence at P.; of the (Marseille, Cocking, B. Density First on Jet International France), 8.4-6 "June B_-ce, Noise. SNECMA Symposium 19-23, 1972. W. D.: and on Air TABLE I.- RANGE AND DEFAULT VALUES OF INPUT PARAMETERS Input Minimum parameter Ae, m 2 N ...... 0.01 ........ r S 5, t m ° ° .... V ........ _ ........ 1 ° " 4 I00 0 0 3O 0. 0001 i i0 0.7 1 4 T" J i0 0.01 ...... A* 3 Maximum "r/4 1 ........ deg Default 0 1.0 0 0.2 C_, _/5 ...... 2OO _, kg/m 3 0.2 ..... 8.4-7 2.5 0 340. 0.9 1.9 1.2 294 400 1.225 !.5 TABLE II.- DENSITY EXPONENT u} lOgl0 Vj/c -,450 -.400 -.350 -, 300 -.ZSO -.200 -,150 -.I00 -,050 0.000 .050 .i00 .150 .200 .250 TASLE -1.000 -.qO0 -.760 -.580 -.410 -.220 0.000 ,220 .500 .77C 1.070 1.390 1.740 1.950 2.000 llI.- POWER DEVIATION lOgl 0 Vj/c -.400 -.350 -.300 -.250 -.200 -.150 -.100 -.050 0.000 .050 ,I00 .150 .200 .250 .300 .350 .400 LEVEL lOglo P -.130 -.130 -.130 -.130 -.130 -.120 -.100 -.050 0.000 .I00 .210 .320 .410 .430 ,410 ,310 .140 8.4-8 lOgl0 P aDgDlOml_.l_- ;;;;;;;7; 0 u% 0 OOOOOOOOO Om_Nm_ 0 C ,-4 I 0 u_ ,-4 O ,.-4 6 O I_.dDl_ 0 I ! 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O u_ m o 0 OC) O0 ¢_ _ 000000000 _._00 (D ¢_00 00000¢_ 0000000 1 8 im _oooooooo_ooooooo_ _OOOOOOOOOOOOOOO_ ,.¢ " 0 0 " " " " " " " _ o o o ! 0 0 _ O0 " " _0ooooo0oooooooo_ _ooooooooooooooo_ _0____ _ _0000000000000000 _0000000000000000 e, v i,, _000000000000000_ _0000_0000000000_ __0___ _O_OOO000000000G_ 0 0 P_ 0 ,-4 _0000_00000000_0_ _ _ _ON_ 00000_0_ 000_0_00_ 0 _Om_ lilll 8.4-19 _ __ _ _0_000 0_0_000 _NO_ 0_ o l, _000000_00000000_ Itlllltlllllllllt i 00000000000000000 % 0 NNNN(¢N¢((IOINI_I NNN_M(¢fOOM(_MNOI OIOQOQOOe0000001D 00000000000000000 00000000000000000 _m_O_mm__ 0 _ _000000000000000_ _000000000000000_ I i 0000000000000000_ 0 r.4 0 B 0 _000000000000 00_ _N__O_O0_ 0 J 0 _000000000000000_ .r,._ > 0 _000000000000000_ 0 J,J 0 U C t_ 0 0 I r, _000000000 _000000000000000_ I 000000_ oq v _0000000000000000 _0000000000000 _0_00_ _N_ __N_O 00__ *'r) O0 O0 t_O00000000 000 O0000 0000001". 0000 00...* _,_0_000 0 NO_ O00 _00_000000_00000_ O0000_NO_ 000_0_00_ 0 lilll 8.4-20 ° _ r ooooo'oooooooooo_ O" 0 _. . . _o_ . • o_ . . __o . 000'0000'00000000_ ___00 0 N 0 0_ * o • _ 0 OOeOOQQQOOeQOOOe r,4 0 0 0 000000000000000_ 000000000000000_ _ oOOOooO_ooeoooooo __o_o_o o _ooooooooooooooo_ _ooooooooooooooo_ 0 0 0 I 0 0 t',,i 000000000_00000_ 000000000000000_ II 8 "_3 U c :> o 0 0 C 0 C_ 0 ,-¢ 0 I _ooooooooooooooo_ _ooooooooooooooo_ " " t_ 0 0 0 I 0 _000000000000000_ _0 00000000000000_ • • • ooee < d 0 0 _0000000000000000 _0000000000000000 _04_00_ _ _m _N_ _m_O00__ A 0 _ooooooooooooooo_ _oooo oo_ooo _oooo_ _000000000000000_ _000000000000000_ U O0000_r CPE_O_,._NOI_O00 000 _i%0 r_ O' 00 O, O_Of_O00 0 ,0_ _._ 0 _ _0_0 _! _NO_r ! i 8.4-21 _ m- - I I I o,o_ _OOOOOOOOOOOOOOO_ 0 o _4___ O_N_ oooooQoeoooooeooo OOOOOOOOOO o o O OOOOOO NNN__OO_N_O_ • • • . • • • . .__ . • ..*_m 0_0_ _Oe_e % r-4 o o _4 ! t_ 0 6 0 o o 1 8 c o o o o o o u oOOOOO oOOOOO __ _m__O_mm_ O_O _OOOOOOOOOO _OOOOOOOOOOOOOOO_ __OO_O_ _m_ _00 ,-4 ! o )...4 ,-4 ! 0 c _OOOO_ _ • O_OOOOOOOOOO_OOO_ OOOOOOOOO_OO_OOO_ O O_O_ _ _000000000000000_ _000000000000000_ _ o _ o. ___ o n. > OOOOOOOOOOO OOOOOOO_OOO _O__ O_OON_ _ _OOOOOOOOOOOOOO¢_ _OOOOOOOOOOOOOOO_ ¢,,! _ O_N_ooOO_ON _NN___N_ b 8 o o .., _OOOOOOOOOOoOooO _OOOOOOOOOOOOOOOO O ,--4 A o c o o o _0000 _000000000000 __0___ _0000000000 _000000000000 _ u _Q O000000 _O_N_O00_ 00000_0_0_000 o E_ 0 ,--4 __;;;;;;;_'_ IIIII 8.4-22 O000_ _ 00_ O00_ O_ O00_ _0 _ _o0o00000o00o0o ° Oo __-___. .. .. ___0___ n _0000000000o000o0 % _00000000000000 _0000000000000000 O0 _0 o 0 _0000000000000000 _0000000000000000 oooo • I 0 0 p-4 o o C_ II e-i 8 _0oooooooooooo _ _O000000000_OOC O_ _oooooooooo_ooooo 0 f* 0 0 0 0 00o00000000o0o0o_ O000000000000000m .__* _.. 0 ..... gO 0 0 I o_ C_ c_ 0 0 I _000000000_00000_ _000000000000000_ .1 rl _S .f.._ o _ ooooooooo _oo 0o0oo 0 _ 0000000000000000 _0000000000000000 oo oooo Oo oo_ oooo_ b, 0 0 _J _00000000_000000_ _0000000000000000 O0000_Om _o_ IIIII 8.4-23 _NO_O0 • _ _o ooo0oooooooooooo o o a) __ _N_ _ i _o000o00000000000 o o r_ gOOOQ60BeOOeOO000 _00oo000000000000 _0o0o0000000000oo 0 eeoeooo6ooooooeoo _oooooooooooooooo o o _oooooooooooooooo _OO___ 0 0 _O_OOO_OOOOOOO_O_ _OO OOOOOOOOOOOOO_ _ _O __O _ o _O_O _ 1 8 0 U 0 0 OOOOOOOOOOOOOOOO_ 0000000000,_00000_ __NO__O_ 0 ,...¢ ! _OOOOOOOOOOOOOOO_ I _ _OOOOOOoOOOOOOOO_ _O____O _N_ ,...1 _OOOO__ s E-'" % _OOOOOOOOOOoOOOO_ _OOOO OOOOOOOOOOO_ O(_((NAOANOONN_ OOeoOOOeO_Oo_Oe_ _N_ _OOOO_O _OOOO _OO OO _OO___O_ OOOOOOOOOOOO _O OOOOOOO m o o o c OOO _OOO_OOOOOOOOOOOO _OOOOOOOOOOOOOOOO eoo_o_ooooo_ooo_o _o _o__OO__o ooooo_ OOO_O_OO_ O_Om _NO_ _ lilll 8.4-24 _O_oo O_O_OOO __O _ _ O_ mooo_oooooooooooo 0 _-. -o_o__ .. _000000000000000_ 0 0 _000_0__ 0 0 _0 p-1 0 0 _000000000000000_ _000000000000000_ _O0_mO_O _ _ •. 0_ .... _000000000000000 _000000000000000_ _00 __0_00_ oo @ • • ! 0 0 o _0000000000000_0_ _000000000000000_ 0 0 oo@@@o@o@@ooe@o@@ __0_ II 0 8 0 _ _ _ _J > 0 0 0 ,-4 ! 00000000000000000 00000000000000000 0 0 r_ F-4 0 _._._._._._.o.-.®_._o.o._. . .• 0 0 0 0 ! _0000 _000000000000000 _0_ 00000000000 _0000 _0000 00000000000_ 00000000000 _ __ _0000_ 0 _ _ _ 0 _ r_ II [-, _8 0 0 [.., r_ v 0 0 0 _0000000000000000 _0000000000_0_000 _00000000_00 _0000000000000000 0 00000_0_ 00_0_00_ 0 illli 8.4-25 O0 _0_00 0_000 O0 _ _ 0 0 _00"00 _000_ • 0 0 r1-4 0 0 oo 00000000000_ • • _*-_ ....... _000000000000000_ • . • . • . • . • . . .__.... _000000000000000_ _000000000000000_ ..... __ 0 0 L_ _000000000000000_ _000000000000000_ _00000__0_ 0 C _0000000_0000000_ _00000000000000_ 0 C 0000000000000000_ 0000000000000000_ 0 _000000000000000_ _000000000000000 o o 0_ • * I U_ t_ E c_ tl L, 0 8 r,. ...4 0 0 0 0 e-, ,..) I I > _ I-N II _C % _000000000000000 _O00000000000000m A 0 0 _0000000000000000 _0000000000_00_0 _0000000_000_0_ _0000000000000000 oooe_oOOooooolooo Illll 8.4-26 I _ "'_oooooo_oooooooo_ O O f.,. 0 0 O ooooooooo ooo- OOBODOOOOOODOO_OO _OOOOO _oo_OO _OON_ ..o OOOOOOOOOO_ OOOOO __ g OOO oOm _O_ . _-''-" _0000000000000_0_ _OOOOO OOOOOOOOOO_ r"- 0000._ O0 _000000 O000000&_ ! O O O 0 O000C c_O00 00'_ | 8 'G U i c" .LJ > O O 0 O _4 O .... , , OOOOOOOOOOOOOOOOO 0-* O000000000000000_n r-I • i* • • • • O f-i ii I O _000000000000000_ _000000000000000_ I _O____O i [.,8 _0000000000000_ _0000000000000_0_ 0 £-* e_ee_e_eeee_ee_ NN_ _00000000 _000000_000000000 _O0___NO_ 0 _0000000000000000 0 0 U eeee_e_eeeeeeeee_ _O_O_N_O0__O O0000_NOm_NO_O00 0 F Ilfil 8.4-27 O_ _N_O000_ 0 _0000000 _o0oooooooo 00000_ _0_0 O_N_ _oo_0_0_ __0_ 000000 moooooooooo _oo_o_o_ _--_*_--*_ _ _g 0_0 .... _00000oooo0o00ooo _oooo0oooo0ooooo_ eO o oe _ 00oo0oooo0 _000000oo00o0o00 _0ooo _ _ _o_''''''_g_''2 $ u'% (_i eeeeee 0 0 _0000000_0_0_0 _000000000 0 _ O000_0 ;_'- II 8 00000000000000000 0000000000000000_ ____ON _u f.. U c_ 0 I o I ,-_ is E- E8 0 _0000000000000 _0000000000000 00_ O0 o _oo0o 400000000000 C _ 0000 O0 _O00000000000CO00 0 _00000000_00000_0 _00000000000 oo00ooooooo_ O000_ IIit11111t1111111 U u_ c_ iilll 8.4-28 I O0 _0000000 O0 O00 _ 0000000000000000_ 0 0000000000000000_ _NO_O_ _ _ O0 _00000_0000000 _000000000000000_ _ O00 o_oeeo • I 0 0 0 0 C _0000000000000_0_ I! 8 0 U % 0 0 0 0 0 ! _000000000000000_ _000000000000000_ _0_ oo oe _N_mO_ _ _N_ C I 0 C ¢._ _0000000000000000 _000000000000000_ ___0__ • 0 0 _0000_00000000000 _00000000000000 __0____ 0 0 O000000000000_ 0000000000000000_ _ _ oo _N_ _ _N _o • • • 11 g _0 q O_ 000000000 O000000 000_0_00_ _ 0_0_000 C N__I iiOli I I I I I I0 _ 8.4-29 L_ 1 o 'oooooooooooooo i • ill i 00000000000000000 00000000000000000 0000000000000000_ 0 eoooooooooeeoeeoe _0000000000000000 0 0 4000000000000000_ _O__OO__ I _ u_ c4 _ _'_ _ _ 0 _OOOOOOO_O_OOoOO_ 0 _OOOOOOOOO OO OOOO_ | 0 "T U > T °- _OOOOOOOOOOOOOOO_ _OOOOOOOOOOOOOOO_ 0 O o O ,--t _O__O__ 0 0 ,,..4 I O ° P'.OOOO_OOOOOOOOOOO •0OOOOOOOO ! OOOOOOOi'_ > <: _0000000000000000 t-4 _OOOOOOOOOOOOOOOO __O___ ° r_ g OOOOOOOOO 0 OOOOOOO_ OoOOOOOOOOOOOO Oo_ _oO_O _oee_e_oo_o_oooeo O__ OOOOOOOOO 0 OOOOO OO OO OO _ O OOO OO _O_ OOOO_ eooeeoooeooeoo_eo _O_O_J_OOO__ _J OOOOO_NO_ OOO_O_OO_ O _O_ _O_OOO O_O_O _ _ IIIII .4- 30 _NO_ OO _ _ _OOOOOOOOOOOOOOO_ 0 _Nme_e_e_e44_o_mo ..... OOOOOOOOOOOOOOOOO QeOOOOOOOOQOOOeO0 00000_0000 00000 0000000 0000000000_ _OOOOOOOOO 0 C OOOOOO _000000000000000_ ___ _ _ _ eee ! O 0 o C _OO OOOOOOO OO OOOO_ I! 8 0 _OOOOOOOOOOOOOOO_ > mOOOOOOO00 OO_ oooooOoooeoooeo_e C C 0 0 ! OOOO O C C I _OOOOOOOOOOOOOOOO _OOOOOOOOOOOoOOO'_ ___O N__ r..oooooooo¢ ,0o oooooooo ooooooo ooooooo II < o _lr" _l A v qr_dl_J ,ml _1 ,-ql _ql t,.4 .,.4 OOOOOOOOOO OOOOOOO _OO_ oeeo_eeeeeeeeeeee OO OO OO000000 OOOOOO _O_O_N_Ooo__ OOOOO_NO_NO_OOO OOO_O_OO_O_O_OOO O_O_m_O_O_ IIIII _.4-31 i ._.. a-i OO OO_OOOOOO_ _ __ O O ,-4 _l OO OO OO OOOOOO_ a,"4 (%1 ('_l (q') OO_ _N O._ _ / j- K j_ J J 00000 _00000000000 0 0 ooolo _eoeoe _N_ 0000000000000000_ 0 0 p,. _4 ooooooeooooeQoooo __ 0o0o0ooooooooooo_ OooooooooooooOoom o _00000000000000 _00000000000000 _0_ o 0 ! _N_ O0 O0 _0_ 0_ .-..4 _ _00000000000000_ _000000000000000 J-I c_ 0 _ 0 tl r-4 8 0 = > 0 0 _0ooooo00o00 _ooooooooooooooom _O_mN oooo_ _mO_O_O 0 0 0 0 ,--t 0 ! _0000000000000000 _000000000000000_ 0 I 0 ¢N =n ___O__m_ II 0 0 r_ 0 0 0 0 0 0 0 _00000000000000 _0000000000000000 _ _0__ O0 _ ooooo0o oooo00o0000oooo0_ o_ oo_oo o _ oooooooom oooooo0oooo O0000G o oo_ _ 0_ 000_0_ oo_ooooeoeOooOooo 00000_0_ 000_0_00_ 0_0_ _ _0_000 0_0_000 _ _ _0 iilll /I . -- 1 1 _OOOOO0'OOOOOOOOO QQO_NN_mNNO % _ _O_ t'0 ,4" ,It OOOOOOOOOOOO OOOO N • . .... • . ...__ . . • • _r_ ,It r _OOOOOOOOoOoOOOO OOOOOOOOOOOOOOOO c ,O N i 0 _OO OOOoo _OOOoOOOOOO oooo o oooo_ oooom I C" _0000000_0_0 00000 ,,1" f-¢ II o _000o0o0ooo0 _00000o C' o 0oo_ 0oo0o0ooo o f'_ 0 ! _000000000000000 _00000000000 0 _ 0000 _M_N_ON__N °_ -C ,-4 ,-# _0000000000000000 _0000000000000000 __0___ _00 O000000000 000000000¢000000_ O00_ 0000000000000000 O000000000000000m _ L' oo_oooo_o_ooooo_o __1J IIIII _1.4- J3 I l J J I 0 _ _oo00o00oo0oo0oo_ o __O_N__O_O OOOOOOOOoOoOOOOOO _ 0 O_ OOOOOoOOOoooooooo OOOOOoOOOOOO _OOO_ ooooooeo_woee_ome _N_O_O__ _OOOO_OO_OOOOO_O_ _OOOOoOOOOOOoOoo_ • o • i 0 B _OOOOOOOOOOO_O _OOOOOOOOOOOOOOOO _o_ °eemOoeeemooeoeee ii o 8 _ooOOoOOOOOOOOOO_ _ooOOOOO_OOOOO _O__N_O_ o (J _n o _O_ _ ,-=1 I I o _O OOOO _ooooooooooooo ___O__N 0 _0000000000000000 _000000000000_000 __O___ O OOOOOoO o ooo OOO oo_ .1 e,n II 0ooooooooooooooo_ _oo___ ooooo°eoeoo_eoe_e o ooo oo o ooooo_ _ 0 _0_ _0_0 °oeoooeoeeoeeeeee u_ 0 00000_0_ 000_0_00_ llltl 8.4-34 000 O0 . "7- _" ..... - *--r. " H. f TABLE VII.- FORMARD r VELOCITY INDEX m(8) deg 0,000 10,000 20.000 30.000 40.00O 50.000 _0.000 70.000 80.000 90,000 100.000 110.000 120,000 130.000 140,000 150,000 lbO,O00 170o000 180,000 8.4-35 .2.. 3,000 1,650 1,100 ,500 ,200 0,000 0.000 .100 .400 1.000 1.900 3,000 4.700 7,000 8.500 8.500 8.500 8,500 8.500 m(@) ...... _ ............... "i ! Y Z Fiqure I.- Schematic diagram of single B.4-36 i stream circular nozzle. .............. r.3 i _J "_o ¢N ? i l 0 u3 l 0 1 I u3 0 l uO ,_. CD I ';uauodx 3 /_,!sua 0 ,q.4- L,._ -- 37 1 t'O e,4 0 •-- OI 0 q3 > ¢., 0 q_ 0 ._l _d 0 e_ o n_ ,-- t_ >_ . I o i q3 L"xi I t.*-) [ 1 l 1 I l 0 • d °LB°I I uo.q.o!^_G J_,Od _.4-38 r_ -J, ,--- ° 'leAe-I I I "_ 0 00 0 cO 0 ¢1,) .-, &-, ¢,I ¢1,1 ::,.. © >o .,-, 4 ° ....4 ¢.< ,-., wO >, "> ,_ w.. 0 cO 0 I,.. 0 0 [ 0 r,,O CO I C] °_6Ol b.4-39 _" + 0 IX:) qr-,.,- 0 U:) 0 0"J ¢{.) 0 _) 0 I l 0 I 8.4-40 -- 0 00 0 0 1I 0 Q) Q) ET_ Q) "I0 o _ "T_ o-4-a o 0 _. k5 -2 (0 o 0 n 0 ,qU $ • ° ° ° 0 0 0 (43 I 8.4-4I , =: J 0 0 0 oo ¢{,> L _o 0 ',m" .m 0 L,. O o t3. 0 0 cN I 0 I 8.4-42 . J. 0 0 0 a) &_ -,3 u < 0 e_ .m ¢{,) = .,-6 ei 0 w,., o 0.. 0 0 i I 0 8.4-43 o (D ('4 0 (N rj w.l tO ,41 U :) L, o > _C) {J _j .Q E 0 0 _D c- > -l,-J i.i ¢3 0 I .,..q ° N [ ) 'JO}t_O..-] UO!}t::3aJJO ! 0 I IDqnoj},S jequJnN a.4-44 (D / 0 > tJ 0 0 .i o 0 ! u_ _J > ._'ao_,._O-I uot_ogJJo::) jaquJnN 8.4-45 IoqnoJ_,S ° -10 _# o -20 -30 _40_------_ _ 110 -50 --70 or -8 -2.0 1 -,.5 I -,.o I -.s Corre¢*,oO I o _Vouh<]l I .5 1 ,.o Number. I ,._ I ._.o lO_h o S, -10 i -20 o_ :_ -7o "._, -60 f _" -so -2.o I -_.5 I -_.o Corre,;teo (a) F_ure 6.- I -.5 SVOUInol Tj,"T,_ = 1.0; Normalized I ._ ' o N=r_ber. lOqlo spectral Vj/c,_ I _.o lo_jt o S. : O. IO0. distribution 8.4-46 level. I _.s I 2.0 r t ....... • r _....-_. rt, i 0 e. IEglEES 90 IO0 110 129 130 -2.0 I I -1.5 -1.0 l I --.5 0 Correcte_ 0 Strouhol L I .5 Numbor. 1.0 IOglo 1 1.5 l 2.0 $, m -10 o -20 -30 -50 -4.0 -60 -70 -80 --2.0 I L L -1.5 --1.0 --.5 Corr_tad (b) Tj/T= L 0 SWo4J_ol Nutria'. = 2.0; lOqlo V;/c, Figure 6.- Continued. 8.4-47 l i L J .5 1.0 1.5 2.0 _og,o S= = 0. I00. I 0 --10 ...." _ -20 -30 _ -5O -- _ -6C -- o --7C -- i -8c --2.0 I --1.5 I I --1.0 --.5 Corrected I I 0 .5 Strouhal Number. IOglo I I 1.0 1.5 1 2_.O S= oF -20 --10 -30 _ -60 _ --2.0 I 1 I --1.5 --1.0 --.5 Corrected (c) Tj/T= J Strouh_ll = 2.0; Figure [ 0 6.- iCglO 1 .5 Number. V]/c Continued. 8.4-48 1.0 Iog,o S= = 0.]25. I I 1.5 2-O 07 o -20 _-- 120 -5C "130 --6C-- -7a--ec -2.o I -1.s 1 -_.o I -.5 Corrected o o 1 o Strouhol I .s Numbs. I _.o iog_o I 1.s 1 2.0 :_, -10 -20 -50 I -2.0 1 -1.5 I -1.0 -.5 Corrected (d] Tj/T L 9.4-49 i .5 Stl'oUhcll = 2.0; Figure [ 0 6.- iog10 Number. V 3,,'c Continued. Ioglo I I 1.0 1.5 S, = 0.150. I 2.0 0 9O 100 110 120 130 . Corrected Strouhal Number. I I Iog_o S_ oV --10 o --20 --30 -40 -60 _ -- 1 --2.0 l --1.5 --1.0 --.5 Corrected (e) T./T 0 Slbrouhol = 2.0; Figure I 6.- .5 Number. lOglo I V3/c Continued. 8.4-50 1.0 Iogto S, = 0.175. l I 1.5 2.0 i 1 -1.5 I --1.0 1 --.S Corrected I 0 5¢ouhoJ 1 .5 Number, 1.0 Iog_o I 1.5 I 2.0 $, oF i, o = --1C -2o --30 o= -40 --50 ;=' -60 o -70 -Sq 1 -- 1.5 1 I -- 1.0 --.5 Correctea (f) Tj/T Strounoi = 2.5; Figure 8.4-51 _jp I¸ 1 0 lOgl0 6.- 1 .5 Number. Vj/c Continued. 1.0 loglo S= = 0.i00. 1 1.5 I 2.0 0 50 Q _ _-8 1 --2.0 I -- 1.5 -- 1.0 1 t ! --.5 0 .5 Corrected Strouhol 1 1.0 Number. I 1.5 J 2.0 Iog_ e S= or - --1 Q "6 '_ 1 --2.0 I - 1.5 I -- 1.0 Corrected (g) Tj/T I. --.5 Strouhol = 2.5; Figwe 1 0 6.- " Nurnbmr. lOgl0 I .5 Vj/c Continued. 8.4-52 1.0 IOglo S¢ = 0.125. J 1.5 1 2.0 0 --,L,'_-C,-_f ..g_ --50 .b a -60 _ - "_ _ 110 120 130 D .b -70, 1 -2.0 1 -1.5 --1.0 J I I I I I --.5 0 .5 1.0 1.5 2.0 Corrected S_ouhoi Number, Iog_o S, =, J= -60"---70 -80 -2.0 I l - 1.5 I -- ; .0 Corrected (h) T]/T_ 1 --.5 0 Strouhol = 2.5: Figure 8.4-53 6.- Number. lOql 0 V3/c_ Continued. I L I l .5 1.0 1.5 2.0 Iog,o S= = 0.150. 0 =, ._ - 100 --60 -7o -80 -_..o I -_.s I -1.o i -.s Corrected --2.0 --1.5 S_ouho! --1.0 Tj/T_ 0 Strounol = 2.5; Figure I .s Number. --.5 Corrected (i) I o 6.- |oglo .5 Number. lOgl0 Vj/c Continued. 8.4-54 I ,.o I I _.5 2.0 1.5 2.0 $. 1.0 Iog_o S. = 0.175. 0 -= ,Q 4= m 120 130 --5C --6C "6 j:J ¢,3 0 --7C --8C --2.0 J I I --1.5 --1.0 --.5 Corrected I I 0 Strouhol .5 Number. Iog,o ; I 1.0 1.5 I 2.0 S. or L_ 0 --1 "5 4= --601--1 I ¥ a- -7o,_--8 -2.0 I I --1.5 ! -1.0 Corrected (j) 1 --.5 Tj/Too = Sb'ouhal 2.5; Figure 8.4-55 1 0 6.- iOgl0 .5 Number. Vj/Coo Continued. Ioglo = I I I 1.0 1.5 2.0 S. 0.200. 0 o: - 10o I --2.0 --1.5 2.0 --1.0 Corrected 5_rouhol Number, L -.5 L o IOg_o $6 0 -20 i -10 -.30 _-'170 -4o_/ _ --50 o -60 0 -8ol -2.o I -_.s l -,.o Correc:ecl (k) Tj/T Strounol = 2.5; Figure 6.- I .5 NumDer. lOgl0 V],'c Continued. 8.4-56 l _.o IOg,o : S. 0.225. I _.5 2.0 oF _--2.0 I I I I --1.5 --1.0 --.5 0 Corrected Strouhol I .5 Number, logic I I 1.0 1.5 I 2.0 S= oF --2C; ->>* -3C -50 -60 -70 -8o --2.0 I I --1.5 --1.0 1 --.5 Correct6cl (i) Tj/T = I I I I 0 .5 1.0 1.5 Strou_al 3.0; Figure 8.4-57 6.- lOgl0 Number, Vj/c Continued. =¢Kj,o S= = 0.I00. J 2.0 T 0 --2 -5 •1:, m o "" 120 130 --6C --7C --8C --2.0 I I I I --1.5 --1.0 --.5 0 Correctea Sllrouhol L .5 Number. Ioglo I I I 1.0 1.5 2.0 S¢ °T --20 _6a£_ 25 --6C -- -so -_.o I -_.o 1 -_ s I -5 Correcte_ (m) Tj/T= 1 o St_'ouho_ = 3.0; Fiqure 6.- I .s Number. lOgl0 Vj/c Continued. 8.4-58 1 1.o 10910 S. = 0.125. [ _.5 l 2.0 r or o e - 120 --60 --70 -80 --2.0 1 I --1.5 --1.0 I I I l --.5 0 .5 1.0 Corrected Slrouhol Number. I I 1.5 2.0 Iogto S, oF -10 o -20 --30 _ -7o -80 F --2.0 I I --1.5 I --1.0 CorrectiKI (n) 1 --.5 0 Strouhal Tj/T= = 3.0; Figure 8.4-59 I l 1 I .5 1.0 1.5 2.0 Number. lOgl0 Vj/c= 6.- Continued. log,o S= = 0.150. 0 -10 N _ .ID I_ -8oi --2.0 I I --1.5 I --1.0 Corrected o o -10 I o --.5 StTouhol I .s Number. I 1.o Iog,o I 1.s J 2.0 1 _.s 2.0 S, 0E --20 --30 !: _ -70 --60_ '_" -8OL -2.o l -_.o _ - 1.5 I -.s Corrected (o) I o Strouhol T3/T _ = 3.0; Figure 6.- I .5 Number. loglO Vj/c Continued. 8.4-60 1 1.o lOglo S, = 0.175. 1 or --20 i --10 --30 _ ._ _ 110 4o -50 -- .m -60"B -70-80 -2.0 , I --1.5 L --1.0 Corrected o_ --10 0 --20 I --.5 I 0 5trouha= [ .5 1.0 Number. Io_lto I I 1.5 2.0 I 1.5 I 2.0 S= --30 _ -40 -50-- lb .m --60---70-- -eo -2.0 I -1.5 I -1.0 I -.5 Correcte_l (p) Tj/T Stro¢_ol = 3.0; Figure 9.4-61 _-. l 0 i .5 Number. lo_! 0 Vj/c= 6.- Continued. I 1.0 IOglo = 0.200. S, e,_gJIE_ gO 10 I I I --1.0 --.5 0 Corrected I .5 StTouhol Number. Iogto I I I 1.0 1.5 2.0 S, 0 _,= _5 i5 4= 5 p- _---i 7o 180 6 t ' -::T --2-0 I l -- 1.5 -- 1.0 I l --.5 0 Correct=KI (q) TilT Strouhol = 3.0; Figure 6.- 1 Number. lOgl0 Vj/c= Continued. 8.4-62 i. I .5 1.0 log_e S= = 0.225. 1 1.5 1 2.0 0 ); o 1 -2-0 1 -- 1.5 - 1.0 I --.5 Corrected • 0 Slrouho| I .5 Number. I I i 1.0 1.5 2.0 IOgso S s --10 " '_ -8oi -2.o i -_.s I -_.o I ., -.s Corrected (r) rj/'r®= I o C:_ouhol 3.5; Figure 8.4-63 6.- lOglg I .s Number. Vj/c Continued. 1 _.o log.> S,= = O.lOC. I _.5 I 2.0 / ,. oF !!o l --2.0 I -- 1.5 -- 1.0 I I --.5 0 Corrected I .5 Strouhol Number. Iog_o I I I 1.0 1.5 2.0 S. oF o -_ -2.0 l I i --1.5 --1.0 --.5 Correct4KI (s) Tj/T I Sl_ouhcd = 3.5; Figure I 0 6.- .5 Number. lOgl0 Vj/c Continued. 8.4-64 .-t! I 1.0 Io_i o S, = 0.125. 1 1.5 I 2.0 r _ -=mms.-:-_w --- -'_ oF -10 -20 -30 --50 _I_ -70 --2.0 I I I --1.5 --1.0 --.5 Corrected I I 0 1 Strouhal .5 Numbw', 1.0 Iog_o I I 1.5 2.0 S, oF --20 i --10 --30 15 -5° -80 --40 _ 1 -2.0 1 I --1.5 -1.0 --.5 Corrected (t) Tj/T 1 0 Strouhal = 3.5; Figure 8.4-65 1 6.- .5 Number. logl0 Vj/c Continued. Iog,o I i 1.0 1.5 S, = 0.150. I 2.0 ............ _ --c _- _ ............................... or o --10 o -50-- 130 .m -60 -- --70 -- --80. -2.0 i I l I --1.5 --1.0 --.5 0 Corrected SVouhol [ .5 Number. iOglo I I 1.0 1.5 J 2.0 S. o_ -o o -30 . --50 ._m -60 (J 0 -70 --80 - :.0 1 -- 1.5 1 I J I I - 1.0 --.5 C .5 1.0 Co4rrect:ed (u) Tj/T S_Ouhol = 3.5; Figure 6.- Number. logl0 Vj/c Continued. 8.4-66 Io9,o S, = 0.175. 1 1.5 I 2.0 • -'J-:-. - 0 _ -10 C 0 50 1_ --60 _ --70 -eol -2.o I -1.s I -1.o I -.s Corrected I o S_ouhal I .s Number. I 1.o loglo I 1.s J 2.0 S= or --10 -20 _ _ --60 --70 or -8o f --2.0 I i --1.5 --1.0 I i I I I I --.5 0 .5 1.0 1.5 2.0 Corrected (v) Tj/T Sti-ouh_ = 3.5; Figure 8.4-67 Number, lOgl0 6.- Vj/c Continued. log_o = S= 0.200. ,/ _k w. • 0 --10 o --20 --30 --50_ --60 -8ok_____ -2.0 --I .5 - I .o -.s Correcte<l I -L____L____L o .5 Strouhol Number. I .o Iogto I 1.5-------2.0 S¢ 0 --10 o -20 _ -50_ u_ _ -6C_ -70 -80 --2.0 '_ l i --1.5 --1.0 I Corrected (w) T_/T I --.5 0 Sll]'ouhcd = 3.5; Figure 6.- Number. lo<910 Vj/c Concluded. 8.4-68 I I .5 -! 1.0 Io@_ o S, = 0.225. I 1.5 I 2.0 Ib Im o n o n 0 0 I ¢_ I I oO r-. (e)ua 1 r,D 'xapul I } la,') _'!oolaA pJDMJOA 8.4-69 0 I t=" ... k_ 8.5 CIRCULAR JET SHOCK CELL NOISE MODULE INTRODUCTION The Circular Jet shock-associated critical by H. tions a pressure K. and a The method can The of SAE shock parameters by the module to of ARP cell and a frequency, Although jet directivity patible table polar it other of the is on to is introduced of acoustic and sound The Aj engine are the pressure that to as a jet nozzle area, reference area, b proportional bandwidth C correlation coefficient C a f ambient speed frequency, of with output angle. azimuthal table is (ft 2) m 2 (ft 2) constant spectrum sound, m/s (ft/s] Hz Helmholtz number, H group _j jet M= aircraft Ne number of engines Ns number of shocks <p2>" m2 source Mach f _e/C strengt/n spectrum number Mach number 2 mean-square reference acoustic pressure, pressure, 2 Pref 8.5-1 x 10 -5 re Pa D 4 c (4.177 function directivity vary the directly required. The input parameters. tables. reference as noise or SYMBOLS A e C func- spectra jet Module azimuthal not so super- Appe._dix spectra produce Parameters parameters of values assumed at proposed master parameters. Noise angle, broadband operating angle. several Jet the employs mean-square noise noise based method the nozzle directivity by the cell angle, is user-provided for each set of predicts function polar directivity shock with The input provided Module convergent method 876. requires be Noise single interference frequency is a The user. Additional is executed once output Cell from ratios. Tanna function Shock noise × 10 -7 Ib/ft 2) com- distance r s from nozzle exit to observer, _ (ft) t dimensionless r distance from nozzle exit to observer, re _e s jet T. total temperature, _ (oR) 3 ambient V. 3 temperature, fully expanded shock cell pressure angle K jet (OR) velocity, interference ratio m/s function parameter, between (ft/s) flight _M_- vector 1) 1/2 and engine inlet axis, deg exponent polar directivity ambient angle, density, kg/m deg 3 (slugs/ft frequency parameter, 7.80S(I azimuthal directivity angle, 3) - cos 8)_jf* M deg Superscript: * dimensionless quantity INPUT The jet noise Parameters Module computation of frequency, polar arrays parameters or the _ne angle, and values of frequency the englne angle, independent to input required Ambient parameter reference distance _ne are user. directivity establish Fin._lly, the are Input reference Ne number of engines N s number of shocks r s distance from area, nozzle Je_ At area of ]et, re in The table fully expanded m2 exit Noise Mach range I. (ft 2) to observer, Parameters A 3et the Constants 3 M for number ] 8.5-2 / J m Noise for levels. directivity engines, required. given Jet required pressure values of the are sound number are either azimuthal variable observer engine and and area, parameters A e from conditions (ft) The angle output table. engine offset and default T: jet 3 v: total fully ] temperature, expanded jet T® re velocity, re Ambient Cam ambient speed M aircraft of Mach ambient Conditions sound, m/s kg/m 3 (slugs/ft Independent polar (ft/s) number density, frequency., c 3) Variable Arrays Hz directivity azimuthal angle, directivity deg angle, deg OUTPUT The output pressure muthal as of a this directivity provided for of angle. _he In from frequenc?, polar table of polar addition, nozzle to Jet the mean-square directivity the obse_2er acoustic angle, and distance azi- rs is observer, Shock m Cell (ft) .Noise Table Hz directivity aza=uthal <p: {f, :,:)>" a Module. Circular f is frequency, Propagation distance r s module function angle, directivity mean-square deg angle, acoustic deg pressure, re _c_ K. Tanna METHOD The _rediction methodology pute _e shock cell noise. _ne method given in exhaust are 2et directivit? of the shock .nozzle _s angles are cell and proposed Details references shown also jet in 1 mixing 8.5-3 the and figure shown. by of i. The Pmise. H. development 2. A schematic _'_..ecoordinate total jet noise is and used to validation of a of typical system will com- be and the sum E ! The normalized associated i/3-octave-band noise is given mean-square pressure for shock by i= n <p2>* = (1.92o × lO-]) L 8 4_(r:) The dimensionless r: and the source = to 2 observer _ - M cos distance (@- r* s is H(O) (i) 6)] 4 defined as (2) rsi_e frequency parameter _ is I I = 7.80_(i - M cos 8) _*. f* (3) 8 i i The pressure ratio parameter is defined as (4) i P I and is a measure parameter exponent number _ of Mj of must the be relative greater the pressure and the 3et shock than ratio total 0 strength. for parameter = D temperature (Unheated 2 (Heated The shock cell pressure noise depends T:J on ratio to the occur. jet The Mach as jet (T; < i.I) with _ > i) jet (T; > I.i} with _ > i) jets with 8 < i) (5) i 4 The quenc/ and is shock (All cell parameter expressed interference _, as polar function directivity Ns-i W angle W = _ a and function of velocity the ratio freV_ N s-(k+l) sin 4 Nsb is 9, [c(_) (bOqkm/2) ]k2 cos (Oqkm) (6) bGqk m k=l m=0 where qkm = l'7--Okrl-v$ L 3 0"06<m + _'_>I (I 8.5-4 + 0"TV; c°s 9) (7) and b • 0.23077. spectrum C t.xluation and 2 3, dB W are in has the tables an II 4 N to Ill Jet, for a by value produce the of cell of equation spectrum plotted value shock coefficient stronqO_ and the The computed correlation source and unheated figure the group value. been t,nqines spectrm, and tabulated plotted of in Per pressure number master (6) qiven the than is two equation respectively. square the (i), le:_s tion The of Ns (I), total in flquros I! should interference • R. it shock of be func- Once is H 2 the mean- multiplied by cell noise. e The pressure output of _p2_* .l=imuthal directivity the pro._._ure gound thi:; as a module function angle. level is a of frequency, In SPL table of addition, defined th,._ mean-square |x_lar printed acoustic _lirectivity output is angle, and available of a._ 2 SPL = i0 loglO <p2>' + 20 (n] loqloP r,! f REYE I. 2. H,irp,,r-_ut'no, ,lad ,h,t:_. i,_,. ll-I II-I T,Inrla, R.tdt.ltiot_ N,:l'.m • °s M.; .*:ul_r..;onLc - 14. K. : Dean, of D.tt.t. l'i:_her, No_.._o KE.N_'E:; M. ,I. : Mech,mi:;m,:, Tht_ Noise From A_K_-CP-[31, ._:hock W, lvo_ H4v. in [,174, _. P. ._u|',,r:;_nic D. ; .In_| l_tlrrin, ,let AF'APL-'PR-7_,-t_S, Not::,,. Voltm_, R. ]!. : Vol_lm.o IV, The I%' - LI.G. Air Ct,n,,t._ttotl and _hock-A._._oct.ltt'd l'orco, ._t,|_t. l'_7_,. j- TABLE. I .- RANGE AND DEFAULT VALUES OF INPUT PAKAMETERS Input Max imum De f,_u I t Max imum parameter 9 Ae, m" . Mr, ........ N . . . 0.01 ..... . ° . . . ",/4 1 1 4 2 S 1O s rs, m 0.01 ....... I00 0.0001 1 0 0 _j ........ T_ . 0 _ ..... ,leq C ,_, D m/' S 1.414 0.7 ....... v" _, o ° ...... ..... i0 0.9 2.0 1 0 1 0 ,3 . ...... , k,;/m ] ]0 340. 200 0.2 294 1.225 S. 5-6 6 3.5 30 400 1.5 ° X [- u_ [-. 0 Z I I I l l l I l I l l I I I I I I I I I I I I I I E-. 0 0 I f • • 2 < [(, :A [.-, 0 I 0 < 8.5-7 oooooQo • I Figure I.- Schematic diaaram of single 8.5-8 stream circular nozzle. _f l t0 0 0 0 0 I/) • ID 4.l e. E o 1,.. 0 a. o t3 O" ¢) 1,,,. la_ l 1 ,0 i I 'u-ln40'_dS I J 1ue!alJ,._aoo 8.5-9 I I UOi]l:)lSJJO0 0 0 0 0 U l 0 b 0 o 0 L, 4.1 U P., r" E 0 I,a 4.; (/1 I,.- 0 I:L U L, 0 0 c0 q _r I I,,- !, ,3 i 0 I i io ,- ,- _ I I I H °L6Ol 'uJru_aads q),6ua.n,S _ I aoJno S dno.J 0 8.5-10 I b 0 0 o .,J U f. C Q_ U Q; ¢; E o n ,-6 _J U Q_ (T Q; i, l l "- ! I I '-- _ Q I ,--I M "uo!'_oun.:t aoua_j._Ul 8.5-11 - i J lla 0 _looqs _J 0 I 0 | e.,-d $ o 0 ! 0 0 I ,_ 'uo!l.aun4 a:::}uaJa:l.Jal.Ul Ila9 8.5-12 )lo0qs 0 c 4J 0 (J ! CJ I I 0 _f3 I 0 0 0 I M 'uo!),oun:l eoueJepe),Ul 8.5-13 i lleO >10oqs _r 0 aO N_ 'uo!_.aun-I aouaJa#a_.Ul ila 9 _aoqs 8.5-14 00 b 0 o_ 0 ..._, E o t,,,O n ,_ e. _ t- o u ! >_ ,,_ ¢- o 0000 ot,.,. i, O 0 0 I ./_ 'UO!_OUn_-] aouajaj.j9_,u 8.5-15 I ii_0 >1oo4s ilJ 0 \ r-o o Q; E -- u0 o L. o (3_ U _.. 0 (J I 0 c- b_ b_ -- 04 0 0 I M 'u0!:[0un__ @::)u_)J;aJJa),ul IleO 8.5-16 'e L >looqs 8.6 STONE JET NOISE MODULE INTRODUCTION The Stone acoustic in the noise. sented in jets The The module _s of Jet angle; noise input be once is a noise angle so than secondary the Noise that The of and table required. input param- pressure the as is reference fully "%. area, expanded jet m2 area, (ft 2) 3 ambient _S speed m/s (ft/s) function for 3et directivity function for shock hydraulic d. sound, directivity equivalent d_ of diameter, m diameter, m mixing noise noise (ft) (ft) .q jet d_ diameter, m (ft) J plug diameter, m (ft) P F spectral distribution factor for jet spectral distribution factor for shock mixing m F 3 frequency, Hz 3.6-1 noise noise a direc- (constant) compatible as directivity azimuthal a (ft 2) m2 or are azimuthal of tabulated output the acoustic exit Module tables. engine prelimited velocity. nozzle SYMBOLS A_ is jet Parameters values independent the as method parameters of is inter- Stone the angle, assumed R. nozzles, mean-square prediction J. parameters. set the Included supersonic. Jet directivity is the each of polar however, azimuthal the by user-provided for table be several by Additional executed exhaust of provided user. may jets. shock-turbulence developed greater velocity mean-square circular and coaxial is far-field coaxial noise that For velocity frequency, tivity o_ can is 2. jet the and mixing used and jet output angle. tion 1 predicts stream jet method requires the The function both t_he core + _rs b? eters. are core method parame directly single references only .Module for The whose Further, flow _oise prediction action to Jet pressure with funcother t L fs frequency shift % configuration factor for mean-square pressure for coaxial Gp configuration factor for mean-square pressure for plug gc configuration factor for Strouhal number for coaxial gp configuration factor for Strouhal number for plug forward parameter flight effects M I Mach nozzle factor number aircraft m exponent N number <_2>" Mach of number engines 2 mean-square <p2( acoustic pressure, mean-square distance Pref reference Rd ratio r S distance from Sm Strouhal S5 Strouhal T fully T ambient V fully of & 2,' & x 10-5 Fa to number for jet shock cell temperature, K jet ratio directivity m m/s (N_ vector angle, (ft) noise (oR) (ft/s) - and 1) 1/2 engine inlet axis, deg angle, density, jet density, kg/m 3 2) diameter (V_)0"Ig, deg deg expanded ib/ft noise kg/m (slugs/ft 3 3) 8.6-2 L -- 10 -7 reference (OR) parameter, directivity angle, observer, velocity, flight x equivalent mixing K 90 ° , (4.177 jet polar ambient 0_c_ for between fully the re = number angle Mach at @ to expanded modified pressure at source temperature, 4 c acoustic diameter jet p _e 2 hydraulic expanded pressure _5 pressure, re (slugs/ft 3) nozzle nozzle .< S- nozzle deg J t azimuthal directivity w density Wo stationary angle, deg exponent jet exponent density Subscripts: i L i primary stream 2 secondary stream i Superscript: dimensionless value INPUT The Noise The jet the distance values polar establish Finally, of are Module frequency, arrays and parameters Parameters the or required the angle, independent variable reference to pseudo-observer the input area, are engine reference N number of rS distance 3 angle area, 41 in the engines, engine The table range from between nozzle exit table. axis and I. (ft 2) flight vector Noise to pseudo-observer, and engine m inlet Parameters fully expanded actual primary stream equivalent actual primary stream hydraulic primary stream Mach primary stream total jet area, re Ae diameter, diameter, number temperature, re T (ft) axis, re re _e Jet angle output Constants m2 8.6-3 ° of required. the required. directivity for Stream primary d;, 1 number of are engines Jet Primary output azimuthal values given Input the conditions and are parameters A e either Ambient directivity engine the from user. deg offset, default ----4 ............ I V 1 primary stream jet velocity, _ primary stream jet density, _eco Ildd t_ ,C . re re O= Stream ._econdary fulty Mr _econdary ._troam Math T: .qecondary .,;trpam total :_econdar\." :;tream _et velocity, secondary stream jot density, J c e-q_anded jet area, re A ¢. numb_,r teml_er,lture, Ambient ambient Th,' sound aircraft ._ach arab.lent density, outVut |'r,'_',_;ur,, .,.q a of thi:; function muthAl d_rect_vity l:; [,rovtd,,d rot r. st_ed, frequency, '_ },olAf ._ Az_muth._l <_,-'tf,_,:)>° c+ re., Condit m/s kq/m _dule ions (ft./._) 3 (.qiu_ls/ft i_ a no::l,, ,'xZt Method 3) tabh, fr,.qucncy, Stone's f T number of from re re of !x_l._r an_l_e. In addition t.h_, Pro[,._q.lt_on Module. ,IX:_tanc,, e the to Jet _he t,%_an-squ.lre ,:irectivity }-seudo-observer },.qeu,k_-obser':er, l_k_se TAble H: ,i_r,,ctlv_,_,:' ,%nq[e, d_r,,ctlvtty me,_n-_quare acou:;tic deg angle, deq _-res._ure. 8.6-4 re o'c 4" acoustic an,_le, and distance m (ft) ._:ir: i METHOD The uses method prediction compute the mean-square empirically spectral developed acoustic determined content of the in functions field references pressure in to with the = the This nozzle nozzles, can with used without each each of coaxial nozzles. showing the figure for directivity , used used The to method and mean-square to nozzle mixing to adjust those for of axis and for fix the amplitude exhaust s_ circular jets. types noise several single coaxial empirically Illustrations coordinate noise supersonic and all jet is used to the and plugs, for which figuration factors are stream circular nozzles predict subsonic schemes one noise, to both and prediction equations, action be including both The basic the overall )> is field. o • 90 2 far field. module types provide computed acoustic pressure .t e 90 o. throughout 1 and the are and developed from determined. inter- Furthermore, the levels predicted for single stream plug nozzles these various directivity two shock-turbulence configurations, angles, are con- single or also provided in i. Jet from The equation the nozzle used exit to Mixing calculate Noise the jet mixing noise at a distance r s is 3/2 l_+[0:12 v[[2_ ] < x Dm(e' In a this equation stationary nozzle exit nozzle exit function, and G = 90 O, at ) @ rs A_e,90°)/ = 90 °, referred Each of the r: is to _e' _) is these < ) >*, is the is now at a flight Dm(@'} _ distance is forward and spectral effects through use of the from the Gc detail. dista.n_e the for distribution directivity in reference pressure f._om factor, provides considered the (!: GcG p acoustic distance dimensionless cal<:ulated 8.6-5 I) mean-square Fm(Sm'@') pressure equation: D the the factors acoustic Hm(M_,@,VI,01,T reference factors, mean-square p2(_e,90° ) is at configuration + 0.62v_ cos 0) 2 + (0.124v[) 1 Fro(Sin,8' calculated Hm(M_,@,V_,O_,T are P information. The <p2( jet I (r:) 2 and following x 10-6 A_,IC_Cv;_75 <p2 (_e.gO °) >"= 2.5O2 (2) [i+ Here, A_, expanded ties 1 the and c for , determined fully density evaluated p_, expanded and the primary - 0.6 (V,*) 3"5 + 0.6 V 1 area, P_ respectively, stream, The of 3"5 jet velocity, respectively. function 2(V_) Loo is jet and density given and V[ with all are nondimensionalized exponent wo the three by is an fully quantiA e, empirically by = (3) & The factor 9' = S m = Fro(Sin,8') @(v_) 0"I and is the a jet function mixing of noise the modified Strouhal directivity number Sm angle calculated by 0, v[Cl- .,,=Iv[, .,_i/2 _) (I In this equation + 0.62V 1 is the f* _)2 cos + (0.124VI)2 Helmholtz / number given gcgP as f_e (5) C M is the aircraft Mach number, and is dj, 1 the jet diameter given as (6) ,5 Further axis, in is the degrees, angle and nondlmenslonalized by _nat over the summation between T_ T is . the the The i/3-octave flight fully vector expanded function and primary Fm(Sm,9') Strouhal 8.6-6 number the jet is is engine temperature normalized unity: inlet such (7) Fm(Sm, e ) = 1 Sm and is tabulated The in table The cussed in function III and Dm(e') plotted factors when table gc the II and in and plotted in figure contains figure directivity 3. gp configuration configuration are factors Gc 2. information and factors Gp of and which is given are equation dis- (i) are considered. Thefo_ard flight e_fects factor _(.®,e,V_,_.T_ is given by + 0.62 (v" l - .®)cose] (1 - _/v1)s(p;)_-_° 1 - M (8) cos.(8 - $) where 0 The function values of the (9) 1 Hm is normalized such remaining parameters: that it is unity if M,_ = 0 for all (I0) The pressure predict configuration predicted for the mean-square respectively. 10 The factors Gp a single acoustic stream circular nozzle pressure for plug and factor <;P and is given * -- Gc take the mean-square acoustic and adjust it to single nozzles, by {Nozzle with plug) [Ii} (Nozzle 8.6-7 without plug) In equation, this i" = Rd With _,i" d* e, 1 d:,ll the plug (12) nozzle hydraulic < = and d:, I, where the A_, 1 these is The factor the is _'_l _C equivalent primary are G c given by _ nozzle quantities diameter, (13) diameter, nozzle area and nondimensionalized given given by d: Ae by is and the plug _e' by l- ,,_/,,_).,+ (l+ ,._,_/,,_,1) _ (14) = (Coaxial 1 The diameter: respectively. nozzle) (Single exponent m is given nozzle) by ,1 (15) The single factor stream respectively. gp or circular These gc jet factors adjusts to that are the for given Strouhal a plug number nozzle or Sm a for single a nozzle, by 0.4 (Nozzle gp with plug) = I (rod) (16) I1 (,Nozzle 8.6-8 without plug) I _J I and gc where fs eter 1 is + A tabulated _- T_fs/,i) -1 = an empirically ; /_; ,2 in ,I table and IV (_o-xial no.-le_ the and The ll3-octave-band noise (3.15 <p2>* _ is this is This ratio param- function is Noise acoustic pressure through .q4 ),I _ I. area due use to of the shockfollowing 10-4)A_ = equation the 4. calculated the Fs(S s) Ds(0,M I) Gc (18) , 2 (r s ) In V2_ figure mean-square interaction of "" ratio in Shock turbulence equation: function " velocity plotted nozzle) (Single determined I pressure - b.4 ratio i -M,,_ cos parameter <_) (_- as follows: _: (.,,_ _ _)1"2 which must be The noise, qreater function for exFanded a than Ds(0,M primary stream (19) zero I) stationa_- (17) for provides jet, on the Mach number shock the cell dependence directivity M I. noise This angle function to of occur. the "_ shock and is the given ceil fully by P _i Ds (_,M 1 } L 1.189 where 0m is '?m = the Mach Arcsin anoie defined & 9 m) (O > @m ) by (20) (IIM I) 8.6-9 i (9 The spectral function Fs(S content s) ss = _ - _ 0.70V the jet total - Fs(S s) far-field mixing The is provided Strouhal through number the Ss: + + is tabulated in table be the for one V and plotted in mean-square by frequency, polar engines noise acoustic noise, equation noise available jet will sum of the shock noise and .,oise. mixing computed SPL cos noise the (21) function The jet of shock on 5. the total the depends 1 The figure of which computed (18), can directivity the mean-square N for the defined the by be output mean-square engine, equation computed angle, is of pressure as and for each In is of angle. by printed sound stun noise, value multiplied and _e shock desired addition, <p2>" the directivity pressure pressure which and azimuthal acoustic table. (i), as the The the number output pressure of is level as 01o: SPL = 10 lOql 0 <p2>* + i0 logl0 2 (22) Pref Power level calculations are not performed by this module. REFERENCES I. Stone, TM 2. J.Imes X-71618, Stone, James Method TM-81470, for R.: Interim Prediction Method for Jet Noise. NASA 1974. R.; and the .Noise Montegani, Generated Francis in J.: Flight 1980. 8.6-I0 An by Improved Circular Prediction Jets. ,NASA TABLE I .- RANGE AND DEFAULT Input parameter VALUES Minimum OF INPUT PARAMETERS Default Maximum 2 Ae, m S o r S s 6, m . o ° . . . ./4 1 ° ...... Aj, 1 ....... d:, 1 ....... i0.0 1 0.01 ....... deg ,1 0.01 ...... 4 i00 0 0. 0001 0 30 1 !0 2 × 10-2/_'_ 2 ....... x I0-2/_'_ M1 ........ 0 1°0 1.25 T_ ........ 0.7 1.0 4.0 V_ ........ 0 1.0 2-5 1°0 1.2 0_ A; 0.2 ........ ,-_ ....... M2 ........ T_ ........ V ° 2 92 •%_ ° • • . . ° . ........ . ° . . • o . 0 0 10 0 0 i 0.7 1 4 0 0 0.2 1.0 1.2 30O 340.194 400 0 ° D , kg/m 3 ..... 1.0 8.6-11 2.5 0 ! .225 0.9 1.5 eooooo oooO IJl|JI oooooooo Jill Ioo OII|||II|II|IIII|II E b.i 0 ,,,,,,, ,,,,,°T_'''''* o,TT "°,, Olle oooo 0 .-.4 oooo oooooo IO I b.1 I II_.O • • 0 I IIIlI "" I I I IllOllIllllIlilllIlIII I II • ! Z 0 moo I ooomooomooooo_oomooomolooooooooo __ I I I I I I I I I I __i___#_e# I I I I J I I I I I I I I I I I O I I t _ * I Ir*l_ I I 0 0 00" _ Ill Illilll llllillllllI|liillili I i [.-, m _l____O_m___O_ oooeoooooooooooooo_ooeeoeooooooo ,4r I "-* 0 ," e, m M 41% ! IIIIIlll C _" 1151 _ _lr_r ! I Illllllllllllllllll I_eel _4M Ol__O__O____m_ • o m iIIIIIOIIIOtI|iIOltIIIIlIIIIOII! _ e,,,e ID •d" ,.it _ I I I IlJlllIIll 0 0 _ I _e,e I IOllllllJllllllllJ I 0 0 0 Z 22 Z X _.o .._0_[, :NI m_m_Om_OO_OO__m_O__ Ul 0 cl I 2 dr.4r_ ! i ! perI_ • m • Iii1111111111 I illllillllilllllll I ! ??T ?? TTTT?TTTTTTT?TTTT,TTT,,,,,,,,_ 0 E .._._._lllllllllO ___ llllllll 8.6-12 D / .f I TABLE III.- JET MIXING NOISE DIRECTIVITY 8, deg TABLE i0 ,40 .45 ._0 ,60 ,70 .?S .80 .90 .95 1.00 1.05 1•10 1.15 1.ZO 1•25 1.30 1.35 1.40 1.45 1.50 1.55 1.60 0.00 -,51 130.0 140•0 -1 •07 -1,56 150.0 -1 160.0 170.0 -2•55 -3•00 180.0 190.0 -3.50 -4 •01 200.0 -4•52 IV.- FREQUENCY SHIFT i0 lOgl0 Dm Dm 120•0 •98 PARAMETER for V_/V_ fs of- 0.20 0.40 0.60 0.80 1.00 0•00 •04 •07 .11 ,14 •16 .19 .21 °24 .25 .27 ,28 • 28 •Z9 ,29 ,30 .30 ,30 ,30 •30 •30 ,30 •$0 .30 ,10 ,$0 •30 ,30 .30 .30 ,30 .30 .30 0.00 .05 •Oq •13 ,17 .21 ,Z5 ,28 .31 •35 ,38 • 41_ ,43 .46 ,4P .51 ,53 .55 ,57 • 59 ,61 •63 •65 ,bb •68 • 69 •71 •72 .73 ,74 ,76 •77 ,78 O. O0 .06 •lZ •18 .z3 •28 •33 •3? ,41 .45 0,00 ,05 ,10 .1S ,ZO ,Z9 .Z9 .33 .37 .40 .43 ,46 •48 ,SZ .54 ,96 ._S9 ,61 ,b:l .64 .65 .68 .69 • 7'0 ,?Z .73 .?4 .?'J .76 .7,7 .78 ,80 .81 0.00 ,04 ,08 .lZ .16 ,ZO .Z3 .Z6 .30 .3Z .35 .38 ,41 .43 ,45 .48 ,50 ,92 ,94 .56 8.6-13 _L lOgl0 110•0 fs 0.00 ,05 •10 .15 .20 .75 ,30 LEVEL ,_1 .93 •56 ,_9 .61 ,6** •65 .67 ,69 ,71 .73 • 74 .79 .77 ,78 • 7,9 .81 .8z .tL3 .84 .85 .86 .60 .61 .63 .65 .66 .67, .69 .7,0 .71 .7,3 .74 .?_ TABLE V.- SEOCK NOISE LEVEL l°gl0 S s -1,8 -1 o7 -1,6 -1,5 -1,4 -1,3 -1.2 -1 ol -1,0 --e9 --e8 --e7 --°6 --,5 --,3 --,Z --°1 0,0 ,1 ,2 ,3 ,4 ,5 ,6 °7 ,8 ,,9 1.0 1.1 1.Z 1.3 1°4 1,5 1,6 1,7 1o8 I0 SPECTRAL lOgl0 i0 DISTRI_3TION Fs lOgl0 -9t,60 -89,69 -84,60 -79,60 -74,60 -69,60 -6_,60 -59°60 -54,60 -_9,60 -_4,60 -39,60 -34,60 -29,60 -Z4,60 -Z9,60 -14,60 -9,60 -7,60 -8,60 -9.60 -10,60 -11,60 -12,60 -13,60 -1_,60 -19,60 -16,60 -17°60 -18.60 -19,60 -20,60 -21.60 -22,60 -Z3,60 -24.60 -Z5,60 8.6-14 Fs T1 Vl X _i (a) Single streamcircular nozzle. :y (b) Figure Dual i.- stream Schematic B.6-15 coaxial diagrams nozzle. of nozzles. o m r. o .M o o_ °_ _,' _ o. I I I I I I I I I ] 1 1 ! 0 0 I ! I _.I ' S_BOI OL ' '10_1 i I uo._n_,l_l!(] I 8.6-16 Io4°lds i ! I I _ -g , I o N.6-17 o o ('1 o a0 o J v E ,qr v- U 0 w Ill .,,,4 • _ X l,J 0 ID _ I C3 0 C,4 i I I ,,- L ¢'4 ! Q "0 °t6o! 0L P_J) I "_!A.qooJ!Q 8.6-18 . 1 o _' I I iJ q m ! °; "Je_,ewo.Jod 1,1!qS ,f 8.6-19 ,_ouenbe._, 0 Q o 0 0 I ! I Ijjjjjjjjto= _ 0 I p'_ ! I "3 °_5°t qf' I OL "le^Ol _ I lID I uo!;nqlJlS!Q IO'lOldS 8.6-20 _"L I_. I _ _ I I 0 -I I _4 8.7 DUAL STREAM COANNULAR JET ._OISE MODULE INTRODUCTION The Dual teristics file. The higher jet Pao by The of and the is a it is tables. in input provided is of Jet table of each of the mean-square directivity angle, noise is introduced assumed so that the values to vary output fully Ae engine expanded reference ambient D speed directzvity d jet area, m2 area, of m2 sound, (ft 2) (ft 2) m/s (ft/s) function equivalent jet diameter, m (ft) eq dh jet hydraulic f frequency, diameter, m (ft) H: .t [ Helmholt: G s_ectral distribution aircraft Mach m forward mass number, velocity flow rate, f A_e#_ function number index kg/s (slugs/s) 8.7-I m . method a thrust, developed by two-nozzle Modul_ or are required. the input pressure azimuthal is compatible exit directly The parameters. as directivity with table pro- has the same The azimuthal SYMBOLS A of acoustic and not the charac- 2. Parameters parameters set the parameters. Noise user-provided on which converts with and noise velocity flow method based the inverted outer, jet 1 several the an The stream references by tot or flow. prediction predicts with se=ondary, single The once jet a Module nozzle primary presented polar the has the Additional executed output angle, noise be Noise exhaust equivalent requires can frequency, Although than an as user. is jet energy. method states module to Jet jet stream Russell The flow Coannular coannular velocity jet flow, and a dual coannular mass Stream of a function angle. directivity with other N number P power <p2>" Pre f r s of deviation mean-square reference from dimensionless S Strouhal S1 first S2 second T total d _O J 10-5 exit Strouhal peak Pa to from 4 (4.177 observer, nozzle exit × 10 -7 m (ft) to Ib/ft 2) observer, re number Strouhal number temperature, K (OR) temperature, velocity, K m/s (OR) (ft/s) spectral peak magnitude specific heats factor ._%2/A 1 ratio of anqle between polar directivity acoustic ref nozzle x distance peak relative = I 2 pc re number ambient j. i pressure, pressure, distance jet factor acoustic r: V engines power, reference jet flight ambient angle, re power, density, kg/m density, 3 (slugs/ft kg/m Strouhal d 1 first normalized second azimuthal dens i ty peak normalized directivity engine inlet axis, DaC3Aeq x r_rmalized and deg 1 J peak vector 10 -12 3 W (7.376 3) (slugs/ft 3) number 5trouhal number Strouhal angle, number deg exponent 8.7-2 x 10 -13 ft-lb/s) deg _e Subscripts : eq equivalent 1 primary 2 secondary jet jet jet Superscript: * dimensionless quantity INPUT of the are The primary Jet Noise required levels. angle table. inlet default and secondary jet Parameters Module for The computation frequency, arrays establish Finally, axis values the the offset, the input to engine reference N number of rs distance angle parameters area, V* 1 Y1 are m2 between nozzle exit to flight vector Jet area, re primary jet total temperature, primary jet velocity, primary jet density, of for of in directivity the engines, required. given pressure table specific A re jet area, re secondary jet hydraulic 8.3-3 engine I. Parameters re T Pm for Jet primary jet Parameters Ae diameter, re (ft) inlet c Secondary secondary and m e re heats observer, _e axis, output engine The (ft 2) jet ratio values number are sound azimuthal engines from l and and Constants Primary primaz- area, observer Input Ae number angle, variable reference distance the Strouhal directivity independent engine and of of polar parameters are required from the output or from the user. Ambient conditions deg range and secondary jet total temperature, secondary jet velocity, 0 2 secondary jet density, Y2 ratio re re T c t of specific re heats for Ambient Co0 ambient speed Mco aircraft of Mach ambient m/s jet (ft/s) number kg/m 3 (slugs/ft Independent polar secondary Conditions sound, density, frequency, D_ 3) Variable Arrays HZ directivity azimuthal angle, directivity deg angle, deg OUTPUT The pressure muthal provided output a: a of directivity for the module of from Double f frequency, polar In a table of polar addition, Module. exit to Stream Coannular the mean-square directivity the nozzle angle, observer observer, Jet m Noise acoustic and distance rs aziis (ft) Table Hz directivity azimuthal is frequency, angle. Propagation distance r s this function angle, directivity deg angle, deg 4 <p2(f,_,_)>" mean-square acoustic pressure, re _c METHOO The noise slngle equivalent energy as pressure _he is prediction jet method which coannular computed jet. as a determ/nes has the The function saume the total i/3-octave-band of frequency, 8.7-4 noise thrust, characteristics mass mean-square polar flow of rate, and acoustic directivity angle, a .J and azimuthal used has coannular the mass m* angle extracted jet The where directivity been nozzle is flow + from p*A*V*. equivalent shown rate of The jet for the references in the figure to conditions. £ and 2. jet is jet the sum A The sc;,ematic method of a typical 1. equivalent equivalent thrust input given velocity of the is by computed thrusts of by the equating individual jets as eq By gas assuming that constant, energy .t meq the the equation T" products combustion jet 71 Yl specific • Yeq " 1 + heat m2 72 ratio m_ Yeq equivalent jet is equal equivalent A, eq - 1 + is the determined by the mass average 72 m2 density to the _ + is found ambient Y2 - i (41 m2 from static = - (V eq the condition pressure. that Rearranging the jet the static perfect jet } (5] 2 area is eq D" V" eq eq (6) 8.7-5 ..... of the -t = a_ value from yields " _he Y1 1 eq and the computed 1 * = -- law affect be "{_2 Y1 gas not (3) •• equivalent pressure can = ml The do temperature as eq The of equivalent ri J _he equivalent jet is (7) =. d_q The diameter acoustic power _* the single stream circular added to this relation to ing expression for _* _%e power ioglO table and is III and The x give_ is table in a jet benefit effects. factor The and 3. is The less and than * the in ratio velocity lOgl0 coannular from a the normalized ii0 O, the (8) ratio 2. The V:q and benefit density is given factor Q ratio lOgl0 V:q_ acoustic power using spectrum function. I/3-octave-band mean-square is <p2>* : eq 4_(r.)2 . -(@ - 6) G(@'CI) for directivity <p2>" angles greater than eq ii0 °, [°(°'°,' = (9) e \ and 0 is result- * figure and velocity figure 4. computed function of plotted velocity figure using is function IT the pressure angle equivalent ratio V_/V_ and plotted in directivity directivity for (^*Weq_'"_'V*t eq1"8p(Veq)Q(Veq,V2/V I)* * of plotted the A coannular double stream power P in function mean-square pr.essure 10 -5) of velocity in table IV a normalized a a calculated acoustic factor is _ is a function and is given For (6.67 deviation V:q_ exponent in = the is jet method. account for ..... _=(r:)__ - _, cos(e- 6)[_ ;_; " 1 ÷_' j\ <_ '-I (I0) %-_ere and r*s = (I0) rs/A_--"., e is loglO V_ •_hich include a and effects. t_vity The angle ar.gle _ d_rection _ spectral is the directivity of given in aircraft forward 9 and allows of The function for polar table Mach flight is given an flight. offset T_._ function directivity V and plotted number M index m(@) in _able VI between ,maining D the terms in equations @ and angle in figure account for is a function and plotted engine in distribution. 8.7-6 inlet equations (g) velocity 5. The forward ratio terms flight of "- Jar direcin fibre 6. The axas (9) and and the (I0) give .. first coannular peak exists for all corresponds values jet has corresponds values to of the expressed in a to the of spectrum the the characterized polar of directivity terms of the of directivity characteristics polar by characteristics the angle Strouhal stream greater than peaks. outer angle. mixed number two the and The second peak ar_ exists for 110 °. defined The stream The spectra are as (Ii) The peak and velocity given Strouhal in number nmmbers the numbers ratio table S2 used log VII O a and function The are peak polar peak directivity Strouhal angle e SI is number ° in Strouhal defined of first figure is given in table VIII to define the spectrum corresponding bers are V* I0 2 plotted 7. The and plotted shape are number. secor_ peak in figure normalized The Strouhal 8. with normalized The Strouhal respect to Strou.hal num- as (T_)0"4 (12) Cl = "_i V;q = i f*d_'2 (T;q)0"4 S 2 V;q - M_ (13) 02 f*d_ - M® and The two relative spectral peaks magnitude factor differ is A e, = in dc=ined magnitude by a factor e'. This as • (14) U(Veq,V2/Vl,B)--&-Aeq The spectral velocity angle in peak lOgl0 _. table spectral The IX All in of of plotted polar noise engines the in and terms in directivity N for the pressure level in equations mean-square the The output can defined i0. and and table. pressure In 8.7-7 addition, pressure directivity a is are given defined by the directivity angle @ and spectral distribution been have for azimuthal mean-square as the (I0) computed acoustic d/mensionless SPL of equivalent polar factor polar figure the the shape of (9) of and spectral values be angle, function magnitude The function O. the of a a V_/V_, peak 9. plotted pressure is spectral as is available u ratio figure number X acoustic frequency, factor velocity G table the mean-square of values StroP,el given total the distribution normalized are and magnitude V_,__ each value directivity multiplied printed <p2>*, The defined. desired of angle. by output the G the The number is sound SPL and the power = 10 lOglo level PWL <p2>" Pref 20 lOglo---_ pc _ defined (15) as H ref PWL = I0 lOglo H* - i0 lOglo (16) O°°c3A_ Ae REFERENCES i. Pao, S. Paul: Inverted 2. Russell, A Correlation Flow James Coannular Profiles. W.: Jets of A Methcd With Mixing NASA Inverted Noise TP-1301, for Predicting Velocity From Coannular Jets .Noise Levels of With 1979. the Profiles. 8.7-8 NASA CR-3176, 1979. TABLE I .- RANGE Input parameter Ae, m2 . . DEFAULT .Minimum . VALUES OF . o INPUT Default i0 I 1 . 0.01 rs, m ..... A_ ....... T[ ....... V _ .... _4 ........ i00 0 0 3o 1 i0 1 6 0.0001 0.7 . . 1.O 0 o 1.0 1.2 1.4 1.5 1.3 A_ ....... 0 0 lO 0.01 1 io 0.7 i 6 0 0 ....... _w 0.9 0.2 ....... ...... 2.5 0 0 71 V_ 4 ...... O, deg _,2 PARAMETERS Maximum _/4 0.01 ..... o AND 2.5 0.2 1.0 1.2 ....... 1.3 1.4 1.5 c, m/s 2OO 294 4OO D, kg/m 3 .... _2 .... 72 " ..... " " 0.2 B.7-9 34(). 1.225 1.5 TABLE II.- POWER l°gl0 DEVIATION Veq/C_ l°gl0 III.- l°gl0 DENSITY _o -!.000 -.900 -,760 -.580 -.410 -.ZZO 0.000 .Z20 .500 .770 L.070 1.390 1.740 1.950 Z.O00 8.7-10 -- f P EXPONENT, Veq/C_ -.450 -.400 -.350 -.300 -.2_0 -.200 -.150 -.100 -,050 0.000 .0_0 .100 .150 .ZOO .2SO lOglo -.130 -.130 -.130 -.130 -.130 -.lZO -.100 -.050 0.000 .100 ,210 .320 .410 .430 ,410 ,310 .140 -.400 -.350 -.300 -.ZSO -,ZOO -.1_0 -.I00 -.0_0 0.000 .050 .100 .150 .ZOO .250 ,300 .350 .400 TABLE FACTOR P -. 0 0 j= 0 _____ ooooo4eoooooooooooooo o ! OI 0 0 0 0 o4 8 0_0_____ ONO__O_O__ _ oeoooooooooeoooeo'ooee 0 0 > 0 ! r,, o 0 0_0_0_00_ _4_0_0_0 0_0_0___0_ ooooooooooeoooeoooeoo 0 E_ O' 0 Z 0 0 0 5 0_0000___0 0_0_0____ 0_0_00__0_ oooooooooooooeoeooeeo __ 0 ! Z < 0 0 0 I ooeoooooooooooooooooo 0 en 000000000000000000000 000000000000000000_00 0 00000_0_0_00_00000000 o4 0_00_0000000000000000 O00000000000 0___0___0 ooeoo_ooooooooeoooooo > E.7-11 O00000 O00 0 u_ O" O" (_0"0" 0_0'0000000_leO0 ,d- 0,0_-0,00,qlhlr--O,ONe.e_l.,..Oqdr_,j,O I I _o f_ I I I I eof_r,- I 0 I ,4"0,0 _¢_ 0"0",0 NqOmO_,O C 0 -;-:.;.;.; I I I _;.:-; I I I I I I I" ; ; ; I" ...... I C if1 ('%1 i _4 0 0 0 8 0 C > .;._.:._.;.:.: I I i I ," _- _- ; ; ," ...... I 0 C _;;;;;_ r_ IIIII ...... II 0 ,.-4 0 .:,IIIII - ; ; -,- ....... ! _0000_00 O00000_C _0 C 6 0000 _000 O000000_ ;;;;;;;;;(;; O000000CO000CO000CO O0 oqDO0 O0 O0000000 • • • e • • • 0 O00¢3000 CO ....... 0 0 • • 0 a.7-12 ¢3G000 ¢300 • • • ¢D¢)000 O0 • • 000 000 • • 000 • O0 O0 • O0 • TABLE VI.- FORWARD 1 deg 0.000 10.000 20.000 30,000 40*000 50.000 60.000 70.000 80.000 9O.000 100.000 110.000 120.000 130.000 140,000 150,000 160.000 170.000 180.000 8.7-13 VELOCITY INDEX re(e) 3,000 1.650 1.100 ._00 ,ZOO 0.000 0,000 .100 ,400 1.000 1.900 3.000 4.700 7,000 8,500 8.500 8.500 8,500 8,500 m(0) 0 000000000 0 ;;;;;_ ! 0 000000000 S g;;;;;;;_ |1 0 0 0000000 __mO c; ! 0 0000000 ;;;;;;i ! 000000000 0 0000000 ! ! ;;;;;;; 0 0 ! 0 0 0 B 0 U U 0_ 0 r,1 ro 0 0 c; 0 Z 000000000 g;;;;;;;; 6 en 0 ;;;;;;; Z 0 0 0 _ 0 0000000 O_ 0 0 _ 000000000 0__0_ 00__ d [.-, ,¢ :Z: 0 0000000 0 0 ;;;;;;; [.., U1 ot _ ,.-4 C C 0 000000000 ¢ "..0 G, 0 0 0 0 0000000 ;;;;;;; CO ! ! 00000000_ > 0000000 if3 0 g;;;;;;;; ;;;;;;; [.., 000000000 0__0_ 0000000 eeeeeee IIIII1! ,,.,, 00_000000 00_000000 000000000 2 _ ggdgggg_ 2 8.7-14 _ 0000000 0000000 000_000 eeeee_e 0000000 0 0000000000000 eoooeooooeeoo 6 0 0 6 0 6 ! 0000000000000 oeoooooooeooo 0000000000000 eoooooooeoooo 0 0 0 9 0000000000000 0 0 a' [,.1 0 0 ,.-4 0 0 0 w_ 6 0000000000000 ooooeooooeoeo 0 0 0 0 0000000000000 6 _o_eooo_ 0 000000000000 I 0 6 eoeoooooooooo 0000000000000 0 _ooooo_oeooe 0000000000000 0000000000000 .0___0_ oooooo_ooooo > 8.7-15 0 0 tr_ o#oeeoeeoeeeo 0 0 a'_ ooooeoeoooooe 0 c_ eooooeeooooeo I 0 8 0 Q _0___ __0__ oeoooeooeeeoe 0 qJ O 0 0 _0_0__ 0 oooooooooeeoo 0 I! I o A 0 0 (3 ,.=e _O_O_N__ __0__ oeeeeeooeeoee (:3 C) _oeeeoe_oo_e _0_0_0_ Q oeoeo_oooeooe ,,==j 0000000000000 0000000000000 O__m_ 8.7-16 m.-_lm.._ _ 0_ 0 _O_mO_ 0 0 (v_0 oooeooooooooo __0_ ooeoooooooooo i U? 0 -.= ooeooeeooeooo O >0 0 "0 .,,,4 0 0 0 ,-,4 0 C_ _0__ ___0_ _00___ oooooooeooeoo OI i 0 ,,.I e_ 0 0 v 6 _0_0_ ooooooooooooo I1! 0 0 6 _ 0___ eooeoeeoooooo liil 0 oooeeoe_eeeee |OJIJ 0000000000000 0000000000000 O__._m_O_ ,-4 "%. > . 8.7-17 _L _ 0 I.n oeogooeoooooo II 0 0 6 II 0 I oeoeeoooeoooe J|| 0 8 0 0 0 __0_ c; ooeeeooeoeeoo ||JJ 0 u_ _00_N__m_ 0 0 0 1,4 0 _O_m__ tO I I 0 o A 0 0 0 _4 ,...1 dr ir_ dD_-iOOS_D d_ dp p,.p.-O _r_ • ,-* I • I • I el, • f I • 0 0 0 oo-eooeoooooee _lllll I 0 | J I I I 0000000000000 O000OO0000000 _oo_oooooeo_o :) 8.7-18 I _DOi%_s'_lr_ O. p..dr O_ dr • • • • • qp dr • • 0 6 o o 6 0 ' 6 _ _0__0_ _00___ eeeoeoeoeeooo 8! _O_N_O_ _N_ _0 N_ _0_0_ 0___ III _00___ _0_ _ _NO0__ oeoooooooooeo I I ! I __0 _ 0 8 U 0 ___0_ _ O _" 0 U 1,4 0 O _n ,--¢ 0 6 I I _00__ _0_ __00__ oooeeeooooeoo _11111 ! 0 •..4 ,,n ........ 0 '0 0 D -,'4 _00__ ;;;;; 0 0 r-4 _0_00000_ d II 0 0 _0__ __00__ Ill __0__ 0 __00_ ooeooooeooooo N_lllII III 0000000000000 0000000000000 0___0_ oeooeoo_ooooo 8.7-19 __ ooooooooooooo 0 0 _NNNNNNNNNNN ooeeeeooeooeO __ _0_ 0 o,I ! _0000__ oooeoooooooeo llllll 0 O" 0 II O_ 0 ,-,.4 U 0 0 u3 ,-I o 0 _J u I __ __0_0_ 0___ oooeeoooooeoe _JO|JJJJ|J fill __N 0 X A C_ 0 0 0 v E-, IIIlll 0 u"l 0 c; oooooooooeooe _N__IIII|I IIIIIII 0 IIIIIIIII -.,4 :> P4 O00000000000O O00000000000O e_oootooeo_ > 8.7-20 [ 000000000000_0000000000000 0 O 0 C _0 _4 000000000000_000000000000000 OOOOOOO 0 C u_ I O ,,-4 0 O0 ___O____ON_ ooooeoooeoooooeooooooooooooo OOOO_OOOOOOOOOOOOOOOO .............. _:___ 0 o ! __OO_O__O_O__O_ Z O 0 O 0 .............. en ____ O 0 I 0 C NNNNNNNNhNNONd_NhNNNNNNNN_hh _O_N_OO_OO_ ooe_oe_eeOOoOoOo_eoo_ooo_oo_ _O__ E_ I 0 O NN_N_ RNN_N_NR_R_NNNR__ r_ _n OOOOOOO___N_O__w C _0__00__ __ _ OOOO OOO OOO OOOOOOOOOOOOOOOOOOOOO_O_OO_O _O___O___O__ _b_o_oooooooooo_oooo_oo_ooe _JiiJlJJlJO I I I OOOOO OOO OOOOOOOO_ _HH_H 8.7-21 .... .. L__ T2 V2 P2 X T1 Vl P l Y Z Figure i.- Schematic diagram of double stream 8.7-22 . ., L - . . coannular nozzle. > 0 ¢, o IJ _, n U 0 > '_ o t_ C',I I I'0 Ll I 1 I I I I I I o _ o,I I.O • d °tS°l " " I 'Ig^a-1 uoqo!^gC] 8.7-23 JeMOd I I / if" ¢.___._ ..... o_ 'l.uauodx3 /q!su_c] 8.7-24 J ,4 (N c,i J ei >- ., 6 _ 0 .a 0 ,_ _ 0. e,i _D N t_ m [ 1 L l ' 0 0 0 °_6°[ 0l- 'lOAO'l ),!]._)UOE_ JDInUUDOD 8.7- 25 0.1 I _0 e Io m _ m (N c,i --q :,r 0 t'N u 0 CJ I e_ o CD m ! L l 0 °_5°I 0 L- l I 0 0 'laAa"11,_eu_E] Jolnuuooo 8.7-26 0 0 8.7-27 o 0 0 0 0 U C 0 U l o 0 I I 0 0 8.7-28 . f- o o o o_._ o © o Qm 0 ! 0 0 C_ l I t I i I (O')w 'xepul X'_,!OOleA P.mM-JO3 a.7-29 0 = o 0 I I I I tS O_5ol 'mqwnN 8.7-30 I I 0 0 0 0 0 0 _ _ , , co 00 , I 0 7 7 I LS OtSOl 'jgqtunN lOLlno_,sMoecl _sJ!_-I 8.7-31 0 0 o • o o o l c_ 4 "j 8.7-32 0 I,,. 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The as a area, m 2 a exponent b span, by c ambient is output of D directivity d tire F spectrum f frequency, G geometry I4 Lg landing-gear K constant £ landing-gear .M aircraft of sound, m/s (ft/s) function diameter, m (ft) function Hz function position strut Mach length, number 8.8-i m the of angle. the dcmi- develFederal and frequency, Each produced by (ft) The the spectrum the wing, aircraft Airframe Noise user-provided executed is frequency, angle. (ft} speed for function Additional (ft 2) m method empirical parameters. module The for a slats. SYMBOLS A a spectra function directivity Center directivity provided parameters. pressure as several be geometry. input azimuthal of can on employs leading-edge input directly spectra noise based Research component and is method azimuthal settings airframe of and broadband method The sound airframe requires and i). produce the the The Technologies (ref. angle, all I ON predicts airframe. United to directivity the tail, of of Module the Administration ass_ned is Fink Noise of MODULE a parameters once table polar Mach Param- of for each the mean- directivity set N number of landing n number of wheels <p2>" mean-square Pre f per landing acoustic reference from gear pressure, pressure, distance r s gear 2 source × re lO -5 to Pa p 24 c (4.177 observer, m × 10 -7 ib/ft 2) observer, re bw (ft) e r s dimensionless $ Strouhal s number distance flap 0 polar of slats for reference 2 ambient , pc.wer, den3ity, azimuthal re 1 D × kg/m directivity _ (ft) deg viscosity, power flaps deg angle, dynamic 7'. m angle, directivity acoustic ref to trailing-edge thickness, deflection ambient _t .. source number boundary-layer _f from c3b _ kg/m-s 2 w 10 -12 3 (slugs/ft-s) W (7.376 (slugs/ft angle, 3) deg Subscripts: f flap h horizontal m_ main landing gear n_ nose landing gear v vertical w wing tail tail Superscript: • dimenslonless quantity 8.8-2 x 10 -13 ft-lb/s) INPUT Theaircraft are required Module or muthal directivity for the the description eters are the The output t_Ible polar range r s distance area, Ah horizontal % vertical % wing area, m 2 bc flap span, m source m 2 to observer, b tail _rea, area, (ft) Geometry m2 m2 (ft 2) (ft 2) (ft 2) (ft) tail vertical m (ft 2) tail horizontal values Constant Airframe flap required I. from Af are distance tail span, span, m m (ft) (ft) V d_c/ d ng ng n ng N_ N..,N S wing span, m (ft) tire diameter of main landing gear, m (ft) tire diameter of nose landing gear, m (ft) main landing-gear strut length, m (ft) nose landing-gear strut length, m (ft) number of wheels per main landing gear number of wheels per nose landing gear number of main landing gear number of nose landing gear number of slots for tralling-edge 8.8-3 flaps conditions Parameters angle, independent default Input ambient Noise the the and and Aircraft directivity establish Finally, The the parameters airframe. in settings, of frequency, arrays Several required. given control the angle table. of is number, either user. output observer Mach from and variable for the to the pseudo- of the input azivalues geometric param- Airframe landing-gear flap Noise position setting, deg A_bient ambient Cop speed aircraft M= O= of Mach Conditions sound, m/s density, ambient dynamic kg/m 3 (slugs/ft viscosity, 3) kg/m-s Independent frequen_I, (ft/s) number ambient polar Parameters (slugs/ft-s) Variable Array Hz directivity azimuthal angle, directivity deg angle, deg OUTPUT The pressure muthal output as of a this directivzty provided for module function of angle. Lhe is a In addition, .Module. from to source the of polar Propagation distance table frequency, mean-square directivity the observer, observer m acoustic angle, distance and rs aziis (ft) r S Airframe f frequency, polar Table Hz directivity azimuthal <p2 (f,_._)>° Noise angle, directivity mean-square deg angle, acoustic deg pressure, re 2 4 D=c_ METHOD _ne method Th.e prediction .Car - field noise. are shown in me_d The figure presented az r_;tame i. The in r_ise reference components definitions 8.8-4 of 1 is used to considered _he directivity compute _n the angles are shown for the is in figure given for In each = equation F (I is the discussion, first is expressed in velocity effect is The Strouhal number S = - the M where L noise is some source The power, D The where K a As as the a is the source to for and functions table Each the The factor forward (i - of the a airframe _* determined different D to on (I), and the given for effects can from each the each be the polar set of compute empirical acoustic mechanism for is trailing edge. T_e turbulence Reynolds number and the with convection acoustic lift the pressure angle, power can and The are The dipole, generation turbulent directivity empirically. 8.8-5 the its own :unctions be computed azlmuthal direc- empirical summarized for clean boundary is length and has these constants in in table III. Noise intensity turbulent The and source Using parameters. acoustic da_a. power. F. directivity noise of thickness. the as component noise function input the surfaces boundary-layer 9) 4 airframe expressed airframe airframe spectrum mean-square frequency, used primarf cos particular II. The directivity and spectrum functions are given airframe noise component is described in detail below. The M (2) Trailing-Edge aligned rs/b w. Doppler (3) equation power, angle tivity is by of the as funcdistance = rs characteristic constants function acoustic by as directivity observer G geometry indicated function for e) scale for G all directivity a are function incorporates and power K (M) and geometry form cos pressure computed. acoustic = method @)4 function. for defined M length being _q* - approach detailed (I) cos dimensionless (i general the F(s) overall spectrum accounted S is fL c M then acoustic * rs the and mean-square D(e,@) )2 _* is far-field _** (i), and following presented component. the 4_(rs tion, is airframe for <p2>* In the method The equation airframe is the 2. prediction assumed scale is function spectrum wing layer to be assumed is function tail the independent to assumed is and past be of the to determined be The acoustic constructed power wing n* ,. The dimensionless the standard due to trailing-edge (4.464 x turbulent boundary-layer turbulent and for the conventionally 14.464 vertical 6: is computed from model -0"2 ./ acoustic = thickness boundarT-layer Aw (P_M.C_Aw_ ii • a (4) <- 0.3, the of 10"5)M56: flat-plate Similarly, noise is × power for IO-5)M _5 tail ,5, the horizontal tail is 161 is 17) • The boundary-layer tion ks (5) using the aerodynamically trailing-edge and (7) should The _s thicknesses for The clean, as such the 7.075 function D a 6v are A and b. or jet of sailplane computed from If the aircraft constants in equations x 10 -6 , an 8-dB decrease. for the clean equaairplane wing and with (4), simple (6), horizontal tail by the = 4 cos 2 _ cos 2 812 vertical directivity sp_ctr_ sin 2 ¢ cos" functions function F(S] = (8) tail = 4 D(@,¢) These values flap mechanisms, be reduced to D(8,¢) and and appropriate directivity given • 6h are F is 0.613(I0S) 4 9/2 (9) plotted given 10S) in figures 2 and 3, respectively. by 1"5 + O. 5]-4 8.8-6 (I0] for rectangular wings and = o.48s(1os)4 lOS) 1"3s + for delta wings. Strouhal These number S f6*b M-'_ = S the appropriate 6" for on the is the M cos value wing, noise t.her for are this of the vertical source being computed The from deployment different span b tail, or and Second, noise the are The wing thu acoustic The either ure 2. tion The The which The = assumes combined then are plotted of 4 slat is in slat from Extension noise incident sion dipole is is of increased. of the is figure the on The deflected dependpres- of layer of the by wing wing. noise. increase Both be to predict used The 2.19S] 1"5 + (8) wing noise along function plotted is clean given in by fig- equa- is of (13) the (12). with the overall s]-4 percent equation to the and noise O. equal directivity equation slat 15 trailing-edge be the is wing to source. by in assumed for The noise increment The their mean-square total t_ sum, to acoustic wing chord. spectrum show the pressure is (I). wing to thick- used increased trailing-edge added by an boundary the 5, noise. is acoustic produces the can given chord given equation assumed turbulence the function S effect to noise for Flap This The method. noise is 0.613(2.19S) the on (4) slat tail produces produces this due sourc_ number computed in function that Strouhal functions either spectrum F(S) impact power noise slat itself for boundary-layer mean-square slats the equation spectrum (i0). its slat trailing-edge for slat 4. Noise leading-edge to Therefore, power for due acoustic slat noise. figure (I). First, accounted added or the leading-edge mechanisms noise of the horizontal predicted. equation mechanisms. trailing-edge in as 8) Leading-Edge-Slat two plotted component (12) - hess sure functions defined (11) (I where ing spectrum is -4 Trailing-Edge flaps be the increases produced flap. noise is flap. 8.8-7 Noise by This assumed the the noise to level lift Increases be of airframe fluctuations aligned as with noiz&. due the to flap the lift the exten- The slotted acoustic flaps power due to flap noise for single or double is Af .q* = x (2.787 I0-4)M6--_ (14) sin 2 6f b_ where overall 6f is the flap acoustic power deflection is angle. For triple slotted flaps, the Af n" = (3.sogx io-4)_ (15) sin2 _ W which increases the power by I dB to account for the added flap complexity. The directivity function D for the flap noise is % cos ¢) 2 D(8,¢) which are = 3(sin is plotted in 6f figure cos 8 + cos 6 for 6f = 6f sin 30° • The spectruD (16) functio_ F (S < 2) F(Sf) = L216.49S; for single and (2 -< S <- 20) O. 1406Sf 0. 04805 f 0"55 double (20 3 slotted flaps (17) < S] and (S < 2) FO.O257Sf (2 <- S < 75) (18} F(sf)= /o.o5365_-°'°625 (75 LlTO_SS_a for the triple slotted flaps. Using the Strouhal number is defined as flap chord as the < S) reference length, fAr (19] Sf = M bfc (1 M cos e) 8.8-8 I The spectrum figures functions 7 and computed 8, from given by equations respectively. equation The (17) The mechan/sm and sidered. the for dependent The predominant to dominate the strut the has noise sources. other potential and wheel are plotted in pressure is then due particular landing-gear simplified made in Noise noise Noise generation been comparisons landing-gear to with the reference i, generated sources. which landing-gear by the Separate are added extension design being assumption, that to are and predictions together based there strut is con- wheel are yield on only made the two appears for total noise. For a noise wheel noise on process experimental (18) acoustic (1). Landing-Gear complex and mean-square oneis or two-wheel landing gear, the acoustic power due to the (2O) and due to the _* Similarly, wheel noise strut = for is noise (2.753 a x is (21) I0-4)M6<_)2_ four-wheel landing gear, the acoustic power due to the (22) _* and due tions to the (20), length, (3.414 strut (21), and The = n and for is the is (22), the = number 3 2 _" sin 2 the d same is of function s_-ut D(8,_) 10 -4)M6n<b_) noise and directivity D(9,¢) x as the tire wheels per the for equation (2_). diameter, landing landing-gear £ In equa- ls the strut gear. wheel noise is (23) @ noise = 3 sin 2 @ sin 2 8.8-9 ¢ (24) Thesedirectivity For a one- noise or for the = 13.59S strut noise F(S} Similarly, wheel = for noise gear, in the figures 9 spectrum and 10, respectively. function for the wheel for the the is defined ÷ S 2)-2"25 {25) is 5.325S2(30 the = + S85 -I four-wheel (265 landing 0.0577S2(i strut F(S) If 2(12.5 gear, the spectrum function for the is F(S) and landing is F(S5 and functions are plotted two-wheel tire noise = + 0.25S2) (275 is 1.280S3(i.06 diameter -1"5 is + used S25 -3 as the (285 reference length, the Strouhal number as fd S The four and strut ooM_c-(l spectrum (I). gear M cos functions are are plotted summed The computed (29) noise The frequency, the mean-square components output pressure polar by In SPL the to the to 14. The separltely total main by landing-gear landing gear wheel using meanand nose Computation pressure the for user. directivity table. level yield due Ii computed separately. acoustic desired figures are to Output _he in pressure then pressure. are @) acoustic They acoustic landing - mean-square equation square = angle, addition, It and printed defined the is airframe computed azimuthal output for is each the directivity is available sum value of of all of the angle for the sound as 2 D / SPL z i0 lOgl0 \p2/ c k* + 20 (30) lOgl0 Pref 8.8-I0 _f J, and the power level PWL defined as 3 2 _.clbw (31) PWL = I0 lOgl0 _" + I0 lOgl0 Href REFERENCE I. Fink, Martin Mar. 1977. R.: Airframe Noise Prediction Method. (Available from DTIC as AD A039 664.) 8.8-11 FAA-RD-77-29, TABLE I.- RANGE Input parame t er rse m AND DEFAULT VALUES Minimum OF IJPUT PARAMETERS Default Maximum 0.01 bw I00 ....... 2 A f, m ...... 0.01 I0 I00 Ah' m2 ...... 0.02 20 200 Av, m2 ...... 0.02 20 200 0.i I00 I000 2 AWl m • o b f, m ....... _ho m . b V, m ....... # ra . dmg, . o . o . . . m ...... dng o m ...... £mg' m ...... £ng" m • . . ...... nng - . . • o o . ........ S • IRg . . ...... "%_ao " 6f, deg ...... Crop # B_/ S . . " • " o ° . . • • • .... . , . • DaD, kg/m 3 ..... _, kg/m- s .... 5 20 0.02 I0 20 _.02 i0 40 0.I 20 i00 0.001 1 5 0.001 1 5 0.003 3 15 0.003 3 15 1 4 4 1 2 4 1 2 4 1 1 2 1 3 3 0 1 1 . ........ Nng 0.01 1.5 x 0 0.3 0.9 0 O 45 200 340. 294 400 0.2 1.225 1.5 10-5 1.7894 8.8-12 x 16 -5 2.0 x I0 -5 TABLE II.- _PIRICAL COHSTANTS AIRFRAME ACCXJSTIC K Source Clean wing AND FUNCTIONS FOR POWER a G and leading-edge slat (conventional construction} Horizontal . . 4.464 x I0 -5 5 4.464 x 10 -5 5 6_c_w)2 4.464 x 10 -5 5 _:Cb,/bw)2 7.075 x I0 -6 5 6: 7. C 75 x 10 -6 5 6h (bh/bw) 7.075 x I0 -6 5 6: (bv/bw)2 2.787 x 10 -4 6 tail (conventional construction) Vertical tail (conventional construction] Clean wing (aerodynamically clean) ....... Horizontal tail (aerodynamically clean) Vertical ....... 2 tail (aerodynamically clean) Single ....... ,,r double slotte_ edge trailingflaps Triple ..... 2_sin _f 2 _f w/ slotted trailing-edge flaps One- or ....... i0 -4 6 4.349 x i0 -4 6 n (d/b_) 2 3.414 x I0 -4 6 n (d/b w) 2 2.753 x I0 -4 6 wheel ....... Four-wheel gear x two-wheel landing-gear noise (_/b_) sio 2 _f 3.509 landingwheel noise Landing-gear strut nolse ....... . 8.8-13 i (d/bw) 2 (t/d) 1 ° T '/ Vl 8 _ I I V 0 v c; 6 c; ,. o.4 v V! ÷ 4, ÷ • ÷ ° • ° Ul UI ;,_ _ t'l U1 0 (/I 0 U1 0 {I] 0 ,,,e • o o o o v CO 0 ql' El3 (/1 8 0 {ti 5.8 8 5.8 _.$ EII I I {/1 Z 0 I I I I EU Z r,. A M L) e., Z C_ C r. % % % 0 U 0 O 0 U '% % 0 O C rj 0 U i 2, % % % 0 U 0 U 0 U _ % "_ m 4- 3 v _a "T O 91 el el "_ 8.8-14 lJ I . A v vl v v! s_ -/ ,4 7 ! ffl T L. ÷ 4. C v O v O _ A A A X_ _8 Z8 X8 I I I ! n 0 i @ 8 I ',,Jr' =:$ ',Jr' X 8 _ X 8 0 I A b.q 0 % e,,i c_ O Ij m t =,, q m % :_11= ..4 o e- "0 C ei q O =11 :1 4'0 m e- 8° 8-15 q ,..4 I I: 11 I., 0 O TRAIL_EDGE FLAPS CLEAN _G VERTICAL TA.IL 0 NOSE _aUl_)nlG Figure i.- Sources of airframe noise included 8.8-16 in prediction model. 9O (a) Variation with polar directivity angle. 2To 90 o (b) Variation Figure 2.- Dir_ctivity and with azimuthal level 8.8-17 w for leading-edge dizectivity clean slat wing, noise. =ngle. horizontal _ail, 90 (a) Variation with polar directivity angle. 27O Figure 3.- (b) Vaxiation with Direc:ivity level 9O azimuthal for directivity vertical-tail 8.a-18 angle. trailing-edge noise. 0 ,.i 0 cq -.4 ¢I or} s,.--. tn 0 .,,a e" 0_ 0 LJ ..(3 E -,,4 0 0 _.. _- t- '0 -,.4 t_ Z 0 c:3 0 U n_ 0 qL (/3 E ! z t_ t_ 1 0 3 8.8-19 .,4 0 4_ 0 0 m I _n E :3 Z m 0 0 cCO O I/ GO U I u_ J,,, °,,,4 l (:3 1 u_ I 3 °_6ol 'l_^el uJn_oed_ 8.8-20 - i I lk! I a I I/ i f_ -- \%/ (a) Variation with / polar J i I I . / /%_t _irectivity / angle. 100 \ 270 I .-_° I I I T _ / ! I i I # (b) Figure Variation 6.- with Directivity at azimuthal level a 30 ° 8.8-21 for flap directivity flap _ngle. angle. trailing-edge noise I 90 [ o 1 l 1 _ o .- _ ,- I I I .:1 °[601 'lava'] I ! o c,i I uJnjload S 8.8-22 o. CM _ _ ol _i I I 01 o n. 0 ¢I 0 q m 0 Z "_ LJ E 4J :3 Z o m ¢I o 0 3Z _. --_ 0 I :> 0 w-4 E '.3 0 I ! OB I i I °° I I i I 0 o _. o. _. ol ! I I I I I -I°_fiOl'l_^el wn4o_d 8.8-23 _ f_ 180 90 (a) Variation with polar directivity angle. 180 270 90 0 (b) Figure £ & 9.- Variation Directivity with azimuthal level for directivity landing-gear 8.8-24 angle. wheel noise. r L 90 (a) variation with polar directivity angle. 90 (b) Variation Figure I0.- with D1rectivity azimuthal level 8.8-25 for directivity landing-gear angle. strut noise. jO _O " u') o o I IJ I 'v'--' I I O I I I I I IZ) O• IZ') ,e O* i I I _-I °LSOI I 'I_A'97 I :'unJ",°_ds 8.8-26 I O O r,') i I ,,,-4 i q I 0 8.8-27 0 0 oi -,,4 O w. e. u_ 0 e- ID E = z " o o _I o e 0 3 Ib- u_ I ¢.,1 0 I:1 I I I I 0 I o I _ I o 0 I _ o I I I I _4 °L6Ol 'IB_B']Lun.qo_)ds 8.8-28 I I I I ,4 0 m 0 _Lr) w L, O P q i 0 m "0 In ,o 0 r'3 Z o r'3 0 ! o L_ 0 W-; in LC') > ,,-,i f L, 0 rJ _., m I ,wP,-,-' I 1 J ! ! I J 0 0 c_ o M I I I 3 °L6ot "l_^_-i wn_ood 8.8-29 I S I I C' 8.9 SMITH AND BUSHELL 'I_I_INE NOISE MODULE INTRODUCTION The noise Smith for and Bushell an axial flow developed by Smith and functions to directivity source is the The and Parameters and to are of output or input pressure with table The a of frequency, Although directivity angle, with other noise patterns The by the Additional a polar it noise is for table turbine turbine A e engine C ro_'oc inlet reference blade ambient C cross-sectional mean speed D directivity d turbine F spectrum f frequency, f" Helmholtz fa fuel-to-air h absolute of area, m2 axial chord, m m/s (ft/s) sound, rotor rotor diameter, m (ft) (ft) function Hz number, fC/c ratio humidity, percent blade tip Mach number 8.9-1 T_ (ft 2) function a Mt m2 mole fraction due to in the turbine Turbine each the directivity introduced tables. area, of noise SYMBOLS A polar noise Noise user-provided once is and significant velocity executed method empirical broadband provided output the frequency parameters. be angle. compatible of the broadband on employs only random is The function is the based method the user. module is function that several the parameters. as a can by predicts The with of directly azimuthal is as parameters directivity I). which input flow Module prediction assumes blades required. the azimuthal vary spectra component, requires exit (re/. method rotating Module parameters acoustic the method entrance The "vortex" of Noise The Bushel1 sound angle. interaction flow. values produce Turbine turbine. (ft 2) is set of mean-square angle, assumed so that not the the M aircraft & mass N rotational Ne number of engines Ns number of turbine <p2>" mean-square Pref Mach flow number rate, kg/s speed, Hz stages acoustic reference pressure, pressure, 2 R dry air gas constant, R gas constant, m2/K-s distance r (slugs/s) from x 10 -5 re 2 source Pa m2/K-s 4 (4.177 2 (ft2/°R-s to 2 pc re × 10 -7 (ft2/°R-s lb/ft 2) re _e 2) 2) observer, m (ft) s r s T dimensionless distance temperature, K ratio of 8 polar directivity r/° acoustic _ref reference ambient power, density, azimuthal Subscripts : i en trance j exit s static source to heats angle, re 1 deg p c3A x 10 -12 kg/m directivity 3 W (7.376 (slugs/ft angle, 3) deg ambient Superscript: * dimensionless observer, (OR) specific power, from quantity 8.9-2 x 10 -13 ft-lb/s) INPUT Theturbine Turbine Noise required parameters for angle, independent variable cross-secr/onal Finally, the are the are are sound values reference given in the mean table number range and engine reference Ne number of r s distance chord, of turbine and of area, (ft 2) e engines from source to observer, Turbine A e C N S turbine inlet rotor blade nummer of axial turbine fuel-to-air area, chord of the re last stages Turbine f (ft) Geometry cross-sectional mean m Noise Parameters ratio a core N* T* _,j mass flow rotational exit rate, speed, static re re P c=/d temperature, re Ambient Cam ambient ha absolute humidity, % aircraft Mach ambient speed density, of camA e T Conditions sound, m/s percent (ft/s) mole fra:tion number kg/m 3 8.9-3 (slugs/ft 3) Ae stage, of turbine distance of Constants m2 the turbine. and values polar inlet number the englnes, the are establish I. Input A The default of frequency, arrays table. axial output conditions The angle descziption area, The the Ambient levels. output geometric required. either user. pressure blade the from the directivity for rotor for engine or azimuthal area, observer parameters of and required required Module com_utation directivity stages are Pa_-ameters re the input to IndependentVariable f Erequency, e polar Arrays Hz directivity azimuthal angle, directivity deg angle, deg OUTPUT The output pressure as muthal provided to a this directivity for the of from is a In addition, Module. source frequency, 9 polar to the mean-square directivity the observer observer, m Noise acoustic angle• and distance azi- rs is (ft) Table Hz directivity azimuthal <p2(f,@,_)>* of polar Turbine f table frequency, angle. Propagation distance r s module function angle• directivity mean-square deg angle• acoustic deg pressure • re 02C _ 4 METHOD The prediction the far-field ure i. The Smith directivity gives the The method noise. A and angles Bushell shown prediction equation in for = in of this reference typical uses figure. vortex far-field _*A* a method broadband the for <p2>* presented schematic D(@) 1 is turbine used is the coordinate The following to shown system prediction compute in fig- and method noise. mean-square pressure for a turbine F(f*) is (i) 4 4_(r:) In equation tion, rs and is (i), Y is expressed rS = _* 2 is (i the the spectrtun in dimensionless - M cos overall @) power, function. form The D is source the to directivity observer funcdistance as (2) rs 8.9-4 The forward (I - M velocity cos @)4. f* = effect The is accounted Helmhcltz fC*_e --(I - for ntmber s= cos by f* is the Doppler defined factor as 0) (3) C whe:e C is The the mean acoustic _* axial chord of for the IO-5)M3_*N t s power = (4.552 H* x the last stage turbine turbine rotor blades. is _4) oe where The N s is blade tip the number Mach of number stages Mt and is m is defined the core mass flow rate. as (5) where N* is ture. The values gas constant absolute ratio The is tion of = F is in a equation local are II function (i). The The the number output is the is a total figure number and acoustic noise of engines available _s of exit static tempera- 7s and values of T_,j, value of fa" function mean-square _he heats The the local the 1.4. in Helmholtz input ratio is plotted is specific from y D and of 3. T_,j of fuel-to-air heats function table and ratio found and specific figure multiplied by tion, printed defined R/R directivity in speed the ha, of given plotted from R* rotational humidity ambient and the the Ne the of polar 2. The is given pressure mean-square for the output sound pressure directivity spectrum in table is then acoustic table. level angle funcIII and computed pressure In SPL addi- as 2 (6) SPL and the Dower PWL = i0 level = i0 loq!0 PWL lOglo <p2>* + defined It + i0 20 lOgl0 Pref as (7) lOql 0 "Lre f 8.9-5 R.I_E 1. Smith, M. J. T. ; and Bushell, in the Civil Aircraft Noise Soc. Mech. Eng., ,Nov. 1969. K. W. : Problem. Turbine Paper 8.9-6 Noise - Its 69-WA/GT-12, Significance American .m ! ........................ TABLE I .- RANGE AND I nput parameter Ae, m 2 ooo.o°oo C Q . fa ........ ° . . ha , % ....... _t . • • .... N _ . o o . Ne ........ T* s,] c, Minim, m o • ° . . . . _ OF INPUT De fault Maximum I0 _/4 0.i 1 i0 0.01 1 100 0 0 0. _6767 0 0 0.2 I0 o 0 0.3 0.5 1 2 0.i 200 340. 294 0 0 oo-oo--o P_, kg/m 3 ..... [S _ • 0.2 NS • • 4 4 400 0.9 1.5 1.225 0.01 # 4 0 I ...... PARAM_ . . . . . . . . _/s VALUES 0.01 ...... A i DEFAULT I00 .... I ........ 8.9-7 l i0 ...... z Q r.. 0 .-¢ 0000 •...................... 0 f.. 00000000000000000000000 00000000000000000 ¢t,l_¢r_iOiDl_m_r_l,.cOe¢l_¢l_¢l o I I I I I I I I I .O_,lr I I I O0 I_*-*_'bID I I I I I 0 0 I A, | ooooooooooooooooooooooo ooooooooooooooooooooooo ).4 i*.¢ 0 ,,-4 0 ,,.¢ .., w_me we _-* m,_ _ I ! I | t | I I 0 ! 0 I 0 I 0 I 0 I 0 ! 0 I 0 I 0 I 0 0 I I I I i z ooooooooooooooooooo ooooooooooooooooooo [-. 0 )., ! ,-*_._¢_,.* i i i I I I I I ooooooooooooooooooo o oooooooooooooooooo o.o.ooooo, oooo.o.ooooooo 00000000000000000 e41ql_4, ti_Ol_._DO_O_l_ 8.9.-8 _'7 -r_'_ O0 4rt_4Dr,,,.m O0 I . _ X Figure i.- Schematic diagram 8.9-9 of typical axial-flow turbine. 0 ,it--- 0 -,-4 0 (0 m (J 0 0 _) 0 K_ "0 ,'m 0 0 "0 e- o_ c< U] 0 O0 o_ L, 0 o lb. _m 0 > r_ o 13_ U 0 0 0 Z ! { I 0 u_ { 0 I t_ I (] °{5°l 0}. 'l_ae-I 0 "I K)!A_:_oj{O 8.9-10 0 I o I .J J . 4J :) 0 F.., 13 0 N 1 0 Z ! [ I 1 I I I I I i I 0 0 _-I °L6ol 01. 'le^e7 8.9-11 wnAoeds I 9. _o PREDICTION PROCEDURES 9.1 ICAO REFERENCE NOISE-PREDICTION PROCEDURE (1978) INTRODUCTION In formed June a of 1977, prediction procedure Lhe applicable subcommittee to were I. Establish 2. Assess an the agreed Oy Identify new noise in SNECMA, Corporation, LocKheed A Lhe in s_mnary of table II. component of _he application measured figure the effective All the of the are standard noise-prediction the in and SST's, an pre- those and to make the internationally British Limited, Each of for these upon. The Douglas General Electric provided and Aerospace McDonnell their predic- currently studies, results a of availreference the subcom- ICAO. procedure used procedure engine interesting are to note level reference by each presented predictions noise perceived NASA, Company, SNECMA results agreed for some each of (P._L) Lhe level (EPNL) participant in table method are variation The procedure is shown The presented wide data and I. computations. noise-prediction noise component included ANOPP me_hod methods in _NOPP functional is in as the ICAO separate modules. presented 9.1-1 %. were by to the differences define Boeing Group. prediction of work The provided on perceived available procedure wi_h to Rolls-Royce was SST is as Aircraft engine Based procedure in the accuracy to various in I. procedure of It the procedure Whitney trial maxim_un of studies associated so noise-prediction the goals against the reference parametric subcommittee presented of in U.S.S.R., procedure were reference results & data. study used procedure engine," the Corporation, SST noise-prediction mittee The noise-prediction "trial problems _he the Pratt trial measured (ICAO) noise-prediction levels between prediction Participating able Organization reference (SST's). reference recommendations Corporation, a the of level recommended and the nc,ise already necessary for a reference of use noise procedures tions Aviation determine transports upon flight-test dicted Company, supersonic accuracy Determine, 4. Civil to to: measured 3. International subcommittee subsequ, reference functional A discussion ently. noise-prediction modules of each or variants component SYMBOLS cr standard c ambient D directivity d fan F spectral f frequenc fp peak ha absolute humidity, percent hr relative htmlidity, percent L acoustic liner role) forward-velocity _2>" mean-square p* of speed of sound, sound, m/s m m/s (ft/s) (ft/s} (ft) distribution 7, function Hz frequency, Hz length, 5 suppression Sc corrected acoustic sea m fraction (ft) pressure, re level 2 pc re 4 Pr pressure, Pa (ib/ft 2) factor 5trouhal ambient mole index pressure, standard jet speed diameter, P,,. T. level function ambient T" sea number temperature, temperature, re K Tr (OR) ] T standard _T thrust T ambient 3 jet sea level loss, temperature, (oR) percent temperature, velocity, re K (OR) c X h_nidi Y vibrational absorption 1 absorption coefficient, ty K ratio function nepers/m (nepers/ft) 9.1-2 J i 8 polar directivity p® ambient Subscripts : cl classical h high £ ic_ max maximum n nitrogen o oxygen ref reference rot rotational sup suppressed vib vibrational densit angle, 7, kg/m deg 3 (sluqs/ft frequency frequency procedure JET The method appendix A Practice Stream in as The 876 of of functions index m(@), tional data of in defined for ratio (lOgl0 data given in are is presented method dimensionless and differs ways. First, 1n table III table IV 0.3 and is The method C Circular Jet functlons as functions of and for SAE Shock a of 876 Cell shock-cell frequeDcy (ref. Noise shock .Module. 9.1-3 in the me_hod Recommended as the Single empirical data produce so_-_ angle. Single Stream Circular forward-velocity 2, is used. F The figure at Second, a value additional addiof the spect=al 3. NOISE I). polar ANOPP to factor included. interference and the figure plotted jet predicting ARP in employs different on Aerospace directivity from and SHOCK appendix polar a based groups distribution of is (SAE) The method V:) velocity This two spectral noise Engineers frequency the NOISE mixing Module. relevant reference Module jet I). Noise terms MIXING Automotive (ref. Jet ICAO !_ise predicting Society (ARP) spectra Jet for of Zircular tabulated 3) cell This is The noise method function directivity is presented in uses to based master produce angle. on ANOPP proposed as the spectra sound spectra in The IC__O the reference Circular Jet mean-square D as 0 additional is multiplied The is method C function given Noise for to in table is V The turbojet, tions of The ICAO method called the figure 5. and than This uses and a is method 2 polar Module. as The is The of ICAO a the interaction Fan 3rages. Noise If second stage spectra is shifted uses Module. taken one to It be similar i/3-octave The ICAO discharge (ref. is 2) only maximu_ total data to to as presented in for of stages, _nree flow. not The preceding higher. multielement Tone last available stage the Fan three for with levels should silencer is the stages a given _he be are as for stage tone spectra reduced by 9.1-4 spectra inlet components dne first two known, then the with first of The _e tone stage. flow is d6 is be if and assumed one a noise for to If assu_ed be a the performance to be similar I/3-octave core/bypass the me_hod computed possible. can n_ise Heidman's discharge-duct noise shifted used. of not broadband if 5 sound NOISE The it on Noise tone stage the Module. used based noise, each components stage, in F_n the are first than mass is the broadband discharge bypass function, plotted predict once the the Noise and flow-distortion engines. and func- angle. inlet tone bypass/fan turboas distribution noise ANOPP to higher uses from spectra spectrum VI DISCHARGE-DUCT method proposed Combustion spectral intake second band the the NOISE executed interaction computed are the reference rotor-stctor the the COMPRESSOR/FAN noise sound table in inlet is for core directivity and data of This functions method tone, performance in presented polar as different INTAKE and on ANOPP Module. given empirical frequency reference rotor-stator from uses is based in produce compressor/fan This directivity 4. angle. Noise predicting Heidman. method functions in directivity polar figure is data to utilizes Combustion of in noise directivity spectrum," for by additional function presented COMPRESSOR/FAN The found i/3-octave-band NOISE engines method the "envelope reference an plotted empirical turbofan reference F by combustion i. and frequency function predicting reference Module. shaft, r_t computed (i) COMBUSTION appendix function The : directivity and an Module. = _(el <p2>" ref additional has Noise <p2>* follows <p2>* angle Cell pressure function The method Shock mixer band or TURBINE NOISE Themethodfor predicting the Smith and the Smith and functions method Bushell to directivity Sm/th Bushell Turbine predict The Bushell Turbine as The me,uhod Fink .Module. spectra 4). The metnod as requires uses angle. Noise in and frequency, The ICAO The tion is Institute low that into is reference the same The where sum a of + is the the relaxation is based as _e empirical and polar no changes of on the report FAA Airframe functions directivity the Noise to predict angle, requires and no sound azimuthal chaunges in the the procedure _rot + the 6.30 the in the ICAO method has ANOPP. American Atmospheric The The the to absorp- Standards ANSI Absorption incor- SAE equations for due reference been National module. equations × 10 -9 that fol- method, Module. classical * 2/2 .... i. 365 (T) [r/Cr)_*. + 0.3713 coefficient in Absorption coefficients × the coefficients absorption 9.20 for This and molecular by Atmospheric = to in as given = 5). Module corresponding absorption is selected (zuf. contained the ABSORPTION Absorption in absorption _vib,n 866A nomenclature acl in ARP method effects defined where similar replace rotational noise method method SAE Atmospheric (ANSI) directly using of the met.hod as Module. atmospheric-absorption porated uses frequency ANOPP assumed polar ATMOSPHERIC procedure of _OPP NOISE presented empirical of component in method method airframe is The vortex Module. predicting This functions directivity Airframe for (ref. presented of AIRFRAME by the is functions reference .Noise is This Module. spectra ICAO noise 3}. Noise sound angle. and turbine (ref. 10 -4 for (f/Cr) nepers Module. nitrogen (T*) I/2 per The and sum (2) p* unit of oxygen length the is as vibrational given by (3) 102"43(T*-I)y(x) ]vib,o t-he parameter X is given -in X = 4.05hrf rr*-l 19 9.1-5 by [41.9 cT*-ll-n. 5]+7.62} (4) and Y(X) is In equation of the the vibrational (4), the absolute absorpt/on relative humidity function humidity h a hr can The Then, absorption average the table VII. expressed in terms lOgl0 T*) (5) h_-10 a total the lowing = be in as (8.4256-I0.1995/T*-4.922 hr given coefficient dimensionless same procedure is the absorption as the ANSI sum of equations coefficient standard is (2) and (3). determined fol- accomplished by method. PROPAGATION Propagation the atmospheric standard (ref. to noise is spectra The tasks and to used. Ground free-field ground effective model levels for a are perceived noise noise in is microphone the (EPNL) is The SAE ARP modeled height. (PNL) Noise spreading, attenuation. presented level by level and spherical attenuation 1.2-m computed is include as and perceived level, observer reflection reflection including noise the performed atmospheric-absorption levels, .Noise sound absorption, the perceived the Module. SAE 5) 2 dB the of Propagation and 8&6A by _"ne adding desired tone-corrected Levels Module. computed by the Finally, Effective Module. SUPPRESSION A variety aircraft silencing _OPP of englne by nozzles. _he suppression quency, polar ICAO These me_hods hate techniques effects for a element effects are of angle, of the below estzmating The ICAO Jet Suppressor all defined types as Subgroup of jet-noise follows: as each a in of of the fre- and table. techniques noise-source by for table angle output recommended may a function directivity effects of and accounted takes implementation suppressor Jet-Noise for quantifying factor S is on for are noise-module provided suppression mixers, module type azimuthal appropriate suppression presented for This the flow suppression suppressor and for lining, noise subcommittee of developed Module. particular prediction the been acoustic Suppression directivity each quantifying have including The General factor multiplies The techniques noise, for component. the also user. be Alter- used. Suppression has produced suppression. ,,p2>" ; a recommended The technique suppression (6) sup 9.1-6 where <p2>* is expression for the unsuppressed the 0.1 S The = maximum been (1+AS) nique are three curves gross given in are incorporate the a in figure of must 7. be Finally, of suppression noise acoustic liner (S meters). The liner Any liner noise is factor = assumed 0.469 L£, should designed noise by is (0.469) of to liner 20.0 designed by to reduce 9.8 dB/m L£ in dB. eter of suggested the to is be where be to same meters. L£ Lh, The produce where A jet-velocity- with ¢ "max velocity. given in function total overall of applied to The table D(@), In is for the value IX as shock dB/m length and given noise (i.0 of in with the dB/ftl liner of in attenuation. suppression addition, an turbine noise will Therefore, the total and noise _ are the will acoustic suppress lining attenuate turbine suppression lengths suppression of should factor S each type be limited Suppression is effective reduction the low-frequency turbine-noise 9.1-7 to 3.3 core-noise LZ intake length the following projected Suppression amount. dB/ft). compressor/fan that is attenuated designed high-frequency (3.0 (0.i03) equivalent V_. a tech- Suppression Inlet-Noise The The studies. jet as Suppression Turbine-Noise turbine 5. latest the has Sma x suppression multiplied directivity Core-Noise core be re'.-city a the figure parametric magnitude jet of of applied. The jet-noise modifications. The in must Shock-Noise no The suppressor data technology, for the jet-noise The use plotted AS the of loss. through and factor of kind Pre-1972 reccmDendation function any AT VIII effects as X, loss table a for performance presented: correction table gross thrust and plotted pressure. is (8) Sma x with suppression AS factor (7) technology, of SmaxD suppression of acoustic suppression I0 correlated function mean-square jet-noise reduced wall be i0 lining limited to dB (S I0.0 for = each 0.100L/d). dB. fan diamIt is Bypass-Duct-Noise Suppression Thecompressor/fandischargeduct noise is (3.0 (S dB/ft) = 6.6 of acoustic 0.103L). dB/m reduce If (2.0 the only (S 4.9 should a maximum the dB/ft) noise attenuation treatment = outer 0.221 dB/m be attenuation on is treated, reduce and if only inner (S = dB/ft) limited to 15 dB. dB is suggested. I0.0 For INSTALLATION The interaction affect the point source ICAO prediction engine SST. noise of the radiated model are often levels to and the airframe to noise is treated, bypass-duct ratios for and 'fhese as recommended account The bypass aircraft. referred subcommittee noise the wall greater than EFFECTS engines from the 0.322L). of dB/m reduced by 9.8 and outer walls inner wall L) (1.5 both the engine installat: a 2.0-dB installation location de-"_tions from the effects. increase effects The in the likely on total a new REFERENCES I. _:as Turbine Eng., 2. Heidman, M. Source 3. Smith, in M. Fink, Mar. 5. Standard Exhaust F.: J. T.; Civil Mech. 866A, Prediction X-71763, and TM Bushell, Aircraft ARP S76, Soc. for Fan and Noise - Automot. Nov. of Soc. Automot. W.: Turbine Problem. Noise from Atmosphere Use Compressor Paper Its Significance 69-WA/GT-12, American 1969. Airframe for Method 1975. K. Noise (Available Values AF_ Interim R.: 1977. H_midity Prediction. NASA Eng., Martin and Noise 1978. Noise. Lhe Soc. 4. Jet Mar. in Prediction DTIC as AD Absorption Method. A039 as Evaluating Aircraft Eng., 1964. Aug. 9.1-8 FAA-RD-77-29, 664.) a Function Flyover of Temperature Noise. 2, ¢r_ .x t t{ T {a L- r. o > II ,¢ ][ *" ! ill 0 < -. [_,.) _3 **. ,( .1. u) ,.-, r- 0 r- ¢, .'< _1 < t- -go_. _g .= E L_ T. (-. 2 N I. I_1 i 5 2 ,2-g _.o = g :}!; i C F I ,1[ II I >. "I ] < ! .¢ J 9.1-9 I. "0 t_ J= Q '0 A ..q 8 C =| ,-6 m '0 e_ q 3 "o ! It _"0 0 E >, ._ 'a. o m g° o_, o I1 0 0 (.., < _n I _J 0 m q ;:_ 9.1-10 = . = .-1 £ • ...4 0 {:3 ,a {j | qD .._ i., _ :_ 0 0 U t U ,.1 0 L.in r- e, I Q M u_ E ,.2 g- < g M _ t- -j L) --,I e_ >.. :j U 3 ,J _L = 3 o ._ -_ _ _= I - I .e < = _ 9.1-II 2 ", _r_ III.- FORWAF_D--V_LOCITY INDEX re(e) deg 0.000 10.000 20.000 30,000 _0,000 50.000 60,000 70,000 _0,000 90.000 I00,000 II0.000 IZ0.000 130,000 i_0.000 150,000 160.000 170.000 180.000 0.000 0,000 0,000 0,000 0,000 0,000 0,000 0.000 0,000 ,I00 .400 ,900 1.700 2.900 _,ZO0 5,_00 6.700 _,000 9.300 9.1-12 M re(t)) ? ! _0000000000000000 _O00_O_N_O_O_O_ 0000000000000000_ O000_Om_O_O_O_ 0 0 ,,,,4 0 0 _D 0000000000000000_ 0000000000000000_ 0 0 0 0 0 e-., ! _0000000000000000 _000000000000000_ I 0 0 0 0 < _._ Z 0 ,,4 0 U [.., cO 0 0 ,.3 _0_ 1,4 0 ii ..r.,_ > a_ 0000000000000000_ 0000000000000000_ ____ ooooooo_oooeooeoo C:n 0 •-.4 0 0 _0000000000000000 _000000000000000_ N_ _O00m_o_OoO_m o mO00000000000000_ _000000000000¢ _0_000_ ,. ! 0 ,..4 OOm mo_o _o0 p.4 n ul 0 0 r,1 _000000000000000_ mOO0000000000000_ ___0_00 v _0000000000000000 0 Z 0 0 _000000000000000_ _0__00_ _ _ _ _ ! > 000000000000000 ,,..1 0 0 0 .-4 00000000000000000 _0___0_ lilll 9.1-13 f O0 0000000000000000 _ _0____ _OOOOOOOOOOOOOOO_ 0 0 _O____ _ ____o • 0 0 _o OOOOOOOOOOO _O _NOO OOOOOOOOOOOO __O_OO_ oe OOO_ OC O000000000000000_ O0 000000000000C _0_0_0_0_00 _ _ O_ I 0 _OOOOOOOOOOOOO_OO _OOOOOOOOOOOOOOO_ r,3 0 | O O_O___ oooooooooooeoeoeo 41*f..._ > O O O _ _ 0 _000000000000000_ _OOO _ OOO oeeo_ooooe_e_eeo __ _O_O__ OOOOOOO 0_ 0 O 0 I 0 > 00000000 0000000000000000_ O0000000_ eeeeeeeeeeeee_eee ___OOO__ II E-, 0 OOoooooooo_oooo OOOOOOOOOOOOOOOOO O_ E-, Oeeeoooooe_oeooeo 0 O 0 _OOOOOOOOOOOOOOOO _OOOOOOOOOOOOOOOO 0000000000000 OOOOOOOOOOOOOOOO_ ___0__0 ooeoooooeeoo_eooo O00_ _O__OO_ _ 0 0 -,4 Oo_ O_O_ _O_OO_ O_OO O_N__ 0 IIIII 9.1-14 / / J _00 0000000000000_ 0 0 CO _ 000 eooooooeooeeeo _ _0_ 000000 __ _ O000000_ 0 0 0000 0000 0 0 • 0000000000_0_ 0000000_0000_ __0__ • o _ • ,-4 _0000000000000000 _000000000000000_ % u') I 0 0000000000000 00000_ 0 0 U 0 > MI 0 0 _0000000000000 _000000000000000_ f.. 0 0 0 ,-_ O00_ O00 0000000 0 ,-4 00_ 0 e,) 0 0 I I _ 000000000000000_ _0000000000000 0 00_ 0 ¢N ,..4 _000000000000000_ _000000000000000_ _0 _ _ _00_'_ oo_o_oooooeo_oooo _ _m_O00__ 0 0 _ _00000000_00000_ _000 O0000000 % O000_ 0 p-I _ 000000000000000_ _000000 0 0 0 u_ 0 0 Illil 9.1-15 _ O00000000_ _ 0 0 CO _000 ,,DO_ CO0000000 C_O000_ O000_ _0 _ O0 O0 _ _ ,IP ,,0 _IP n C 0 000000000000_ r_O,O 0 0 _D _00 _00 _00 CO00000 CO000000000 O000 oeee_o_be_e_ _' N ,It _OOCO00000000000_ _000000000000000_ 0 0 _O_C_O0000000000_ II n n. 0 (D 0 0 LJ 0 0000_00000000000_ 0000000000000000_ _u_ _0_ _ _ _ o_ooeeD_oeo_oeoe _'_0000__ 0 _ o I t b-q 0 0 I_ 00 O00000000 _0000000000000000_ ,,.-01_,_ O_ _t_'_ 0 _00000000000_000_ _000000000000000_ II a_ 3 IIIII 9.1-16 _,CD _0 _'t _ .4" _ _lr 00 _ t_.. _r_ ,0 000000000000-,11" _000 0 _O_O 0 00 ,-4 Jd2g O 0 OOOOOO OOOOO COOO_ _OO_ 0 ,...4 OOOOOOOOOOOO OOOOOOO 0 0 OOO O O OOOOOOOOOOOCOOOO OOOOOOOOOOO_OOO_ NN__O_O_O_ t_ ! 0 0 c_ 1 _3 o _O_ 0 u_ :> 0 0 o,3 0 ,-.i c 0 _OOOOOOOOOOO_OOO_ _OOOOOOOOOOOOOOO_ _O__O_ 0 ,,..-4 _0000000000000000 _O0000000000CO000 0 0 I _0000000000000000 _OOOOOOOOOOOOOO_O 0 0 > ! 0 ,....4 II < [..., 0 0 0 C 0 0 _000000000000000_ _000000000000000_ _ _0_ eeoee_eeeeoeeeeee 0000000000000000_ 0000_00000000000_ _00_0__ g g2g ilddd g 2 OOOOOOOOOOOOOO_O_ OOOOOOOOOOOOOOOO_ ooeoooooo_ooooooo _J O IIIII 9.1-17 __ _0_ 0 5" 0 00000000000000000000000000 00000000000000000000000000 _O00_O0_OONO_O00000_O_O0_ oouooeooo4o_eoDeeeeeeooooo I a, Z S a m J I J I t I J I f! Z r_ _00_00000000000 0_0000000000000 0_0_0_0_000000 ooe_o_o_eeooe Z r,,. J I J J J J I J I I J J J J J 00000000000000000000000000 00000000000000000000000000 _O___O_N__O_ _2(((;;(;;(_ r. J _ @ ) v' I 000000000000000 000000000000000 000000000000000 ! :> 9.1-18 ........ • • eee_ .__..__ I TABLE VII.FOR MO_ VIBRATIONAL SAE ATMOSPHERIC ABSORPTION ABSORPTION METHOD x Y(x) 0.00 .25 0.000 .50 .315 .700 .60 .840 .70 .80 .930 .90 1.00 .996 1.000 i.i0 1.20 .970 .900 1.30 1.50 .840 1.70 2. O0 .670 .570 2.30 .495 2.5O 2.8O .450 .975 .750 .40O .370 .330 3. O0 3.30 .300 3.60 4.15 4.45 .260 .245 4.80 .230 5.25 .220 5.7O 6.05 .210 6.50 .205 .200 7._ I0.00 .200 .200 9.1-19 FUNL'TION TABLE VIII.- MAXIMUM JET-NOISE SUPPRESSION Sma x, dB, for FACTOR - _T, Recommended percent Demonstrated for \ Latest pre-1972 parametric technology technology studies 1.000 2.000 4.0O0 6.000 8.000 I0.000 12.000 14.000 16.000 1_.000 ZO,O00 0.000 2.200 4.600 6.000 7.000 7.600 8._00 8.800 9.200 9.800 I0.000 TABLE IX.- JET-NOISE VELOCITY 0.000 5.100 10.400 13.400 15.700 17.300 18.bOO 19.800 20.800 21.700 22.600 0,000 3.5O0 6.200 9.300 I0.800 II.900 12.800 13.700 14.400 15.000 15.400 SUPPRESSION FACTOR CORRECTION v* As 3 0.000 1.070 1.250 I..30 l.bl0 1.790 1.970 3.000 -1,000 -1.000 -.800 -.bOO -.400 -.ZOO 0.000 O, OOO 9.1-20 ? \ I TABLE X.- DIRECTIVITY JET-NOISE FUNCTrON FOR SUPPRESSION _B deg D (@ ) _30 0 6O 8O .3 .5 i00 120 1.0 .7 >120 1.2 9.1-21 ._ q - L ................... ° ._ U U 0 f- E l, m E 0 o t_ L] U 0 _ E U 0 _, e,.,,-4 -,,4 0,1 [] 0 x S r" '-' E 0 0 t_ 0 > 0 I 0 0 t_ .,,,,i I t I 1 ! J i i 9.1-22 .. _ _ _i _ I __ M N L 0 0 0 ,,¢ o I,,- 0 0 (:9 -g <: o iI Wl_ gm 0 • o £3 ,,, _0 O 13_ "0 0 ('4 I 0 I (8)w I 0 0 0O 'xapul _[o01aA-PJDMJo3 9ol-23 i -J --3 g - 100 120 130 _" -75[ -2.0 I I --1.5 ] --1.0 I --.5 Corrected I 0 I .5 Strouhol Number, 1.0 I 1.5 I 2.0 log m S. a =, 4 7 -2.0 l --1.5 1 1 I -1.0 --.5 0 Corrected (a) Figure 3.- Tj/T S_ouhal = l.O: .Normalized Nurnber. loglo spectral 1 .5 V_ I I 1.5 2.0 S, = 0.3. distrzbution 9.1-24 Ioglo I 1.0 factor. O, DEGREES 9O 100 110 120 130 1 -- 1.5 -- 1.0 1 --.5 Corrected 0 Strouhol I I I I .5 1.0 1.5 2.0 Number. log10 S o --35 , -45 --2L -- _5 170 -55_ -65 ( -751 --2.0 I 1 I --1.5 --1.0 --.5 Corrected (b) 1 0 S_ouhol Tj/T = Figure 9.1-25 2._; 3.- I 1 I I .5 1.0 1.5 2.0 Number. lOgl0 Continued. log,o V_ = 0.3. S. m o _U,_ __" '_ II0 "130 -7 --2.0 I I --1.5 --I.0 Corrected • t I I I I -.5 0 .5 1.0 1.5 2.0 Strouhol Number. lOg_o SQ ), DEGREES SO "160 70 180 I I -- 1.O Corrected (c} Tj/T® I --.5 Strouhal = 2.5; Figure I O Number. lOgl0 i .5 1.0 Iog_o S_ v_ = 0.3. 3.- Continued. 9.1-26 DEGREES 90 10 130 _l L -- 1.5 1 -- 1.0 1 --.5 Correctsd 0 Strouhol I I I I .5 1.0 1.5 2.0 Nurr_m'. log m S= I L_ o oc -45 _"/ \_ 160 170 180 JD i5 J- :_ -s5 --75 --2.0 [ -- 1.5 [ -- 1.0 I [ ! i I --.5 0 .5 1.0 1.5 Corrected (d) Tj/T StrotJhol = 3.0; Figure 9.1-27 3.- Nun"_e'. logic lOqlo v_ = 0.3. Continued. S, J 2.0 la,. "130 _'120 --4_ --5 _-_ -2.0 1 -,.s 1 -_.o I -.5 Correctecl -4:_ ._L#e -_ --2.0 1 o Strounol I .s Numoer. I _.o 1 _s I 2.0 IOg_o S, _ "180 "170 1 1 I I --1.5 --1.0 --.5 0 Corrected (_) Tj/T Figure = Strouhal 3.5; 3-- 1 .5 Plumber. ic_l 0 V_ Concluded. 9.1-28 = Iogso 0.3. I I I 1.0 1.5 2.0 S, 0 ,--m &,- Cn _, t..i _- "o ,- >', = > o < o-- ! 0 _.- 0 0 I .,-4 0 [ _J El °tB°l I L 0 0 O L 'le^e7 X_,!^.P, ogJ!(] 9.1-29 Z_ ..... mo ur) o 0 c o 0 __ m O = d 8 t_ o _ E O E u _ I_" IlJ e_ e - u_ I "-4 0 I m m I --2 u'3 I I [ 0 .,-- I 0 I I I 0 ,- 0 04 0 F'_ I I I ._ °LfiOl 01, 'l_^e7 uJn_0eds 9.1-30 m,,..z_... Io I J o 0 .-i I'--- -_ C E x I,- E I O O O U3 _4 8P _'"S 'uo!ssajddns wnw!xol_l 9.1-31 ___:_L._ 0 t ______.__L___J o 0 u') SV 'J°_°°3 u') I uo.qoajJo3 CD u') ,__ I I uo!ssajddns 9.1-32 0 c,i