Recent Research Review
Hui HU
Advanced Flow Diagnostics and Experimental Aerodynamics Laboratory
Department of Aerospace Engineering
Iowa State University
2251 Howe Hall, Ames, IA 50011-2271
Email: huhui@iastate.edu
Summary of Recent Research Activities
Velocity, temperature,
Density, Species concentration
, etc..
Flow
measurement
techniques
Intrusive
techniques
NonNon-intrusive
techniques
• Pitot probe
• hotwire, hot film
• thermocouples
• etc ...
particleparticle-based
techniques
moleculemolecule-based
techniques
•
• Laser Induced Fluorescence (LIF)
• Molecular Tagging Velocimetry (MTV)
• Molecular Tagging Therometry (MTT)
• etc …
Development of advanced flow diagnostic techniques and instrumentations:
•
•
•
• Laser Doppler Velocimetry (LDV)
• Planar Doppler Velocimetry (PDV)
• Particle Image Velocimetry (PIV)
• etc…
etc…
ParticleParticle-based flow diagnostic techniques:
• Laser Doppler Velocimetry (LDV) technique.
• 2-D Particle Image Velocimetry (PIV) technique
• DualDual-plane Stereoscopic Particle Image Velocimetry (DP(DP-SPIV) technique.
MoleculeMolecule-based flow diagnostic techniques:
• MoleculeMolecule-based Microscopic Flow Diagnostic Techniques for in Microflow Studies.
• Novel Fluid Temperature Mapping Technique with Adjustable Temperature
Temperature Sensitivity.
• Molecular Tagging Velocimetry and Thermometry (MTV&T) Technique (US Patent Pending).
• Novel technique for Quantification of Molecular Mixing in Gaseous
Gaseous Flows.
Fundamental studies of complex thermal-flow phenomena:
•
•
•
•
•
MicroMicro-scale flows and MicroMicro-scale heat transfer in Microfluidics.
Microfluidics.
BioBio-inspired Airfoil and Wing Planform Designs for MicroMicro-AirAir-Vehicle (MAV) Applications.
Film cooling and trailing edge cooling of turbine blades.
Buoyancy Effect on the wake Instability behind a Heated Circular Cylinder.
Lobed Exhaust Ejector Systems of AeroAero-engines.
Particle-based techniques: Particle Image Velocimetry (PIV)
•To seed fluid flows with small tracer particles (~µm), and assume the tracer particles moving with the
same velocity as the low fluid flows.
•To measure the displacements (ΔL) of the tracer particles between known time interval (Δt). The local
velocity of fluid flow is calculated by U = ΔL / Δt .
at t = t0+ Δt
1000
ΔL
left camera
900
900
800
800
700
700
600
Y PIXEL
Y PIXEL
right camera
1000
500
600
500
400
400
U = ΔL / Δt
300
300
200
200
at t = t0
100
100
0
0
0
0
500
500
1000
X PIXEL
1000
X PIXEL
A. t=t0
X
Laser Sheet
Spanwise Vorticity ( Z-direction )
Y
Y mm
200
-25.00 -20.00 -15.00 -10.00 -5.00
0.00
5.00
10.00 15.00 20.00 25.00
water free surface
150
Z
Z
X
Re =6,700
30
Uin = 0.33 m/s
α2
20
α1
50
10
0
U out
0
-50
-50
0
50
100
150
-10
X mm
200
250
-20
300
Camera 1
C. Derived Velocity field
B. t=t0+4ms
Classic 2-D PIV measurement
Camera 2
-30
-40
-30
-20
-10
-40
0
Xm
10
20
30
Stereoscopic PIV measurement
Y mm
100
W m/s
20.00
19.00
18.00
17.00
16.00
15.00
14.00
13.00
12.00
11.00
10.00
9.00
8.00
7.00
6.00
5.00
4.00
Dual-plane Stereoscopic PIV System
z
• Vorticity vector is defined as the curl of the velocity vector :
∂v ∂u
ϖz = − ;
∂x ∂y
Measurement plane
∂w ∂v
∂u ∂w
ϖx = − ; ϖy = −
∂y ∂z
∂z ∂x
x
y
“Classical”
Classical” PIV or SPIV systems can only
measure one component of vorticity vector
• Polarization conservation characteristic of Mie scattering is utilized to
setup the dualdual-plane stereoscopic PIV system to achieve simultaneous
simultaneous
measurements of velocity vectors (three(three-components) at two spatially
separated planes .
z
P- polarization(horizontal)
x
y
S- polarization(vertical)
polarization separation method
Half wave (λ/2) plate
Mirror #1
Double-pulsed
S-polarized laser beam
Mirror #2
cylinder lens
P-polarized
laser beam
Host computer
Nd:YAG Laser set A
Double-pulsed
Polarizer cube
Laser sheet with
S-polarization direction
Nd:YAG Laser set B
Laser sheet with P-polarization direction
Synchronizer
Measurement region
80mm by 80mm
Lobed nozzle
Polarizing beam splitter cubes Mirror #4
high-resolution
CCD camera 4
650mm
25 0
0
high-resolution
CCD camera 3
25
650mm
Mirror #3
high-resolution
CCD camera 1
high-resolution
CCD camera 2
Vortex structures downstream a lobed mixer/nozzle
( Laser Induced Fluorescence (LIF) Flow Visualization Results)
X/D=0.25
X/D=0.5
X/D=0.75
X/D=1.0
X/D=0.75
X-Z plane
X-Y plane
X/D=1.5
Y
Lobe peak
H=15m
m
Lobe trough
Z
X
X/D=2.0
The Simultaneous Measurement Results of the
Dual-plane Stereoscopic PIV System at Two Parallel Planes
20 m/s
20 m/s
Y
30
Z
20
x
Y mm
10
0
30
W m/s
20.00
19.00
18.00
17.00
16.00
15.00
14.00
13.00
12.00
11.00
10.00
9.00
8.00
7.00
6.00
5.00
4.00
3.00
X
-10
-20
Z
X
20
10
0
-10
-20
-30
-30
-20
-20
-10
z
-10
0
0
10
Xm
m
Xm
m
20
30
20
30
40
40
-1.0
40
10
B. the simultaneous velocity
field at Z=12mm plane
A. Instantaneous velocity
field at Z=10mm plane
40
W m/s
20.00
19.00
18.00
17.00
16.00
15.00
14.00
13.00
12.00
11.00
10.00
9.00
8.00
7.00
6.00
5.00
4.00
3.00
-30
-30
Y
Y mm
Y
-2
.5
4.50
3.50
2.50
1.50
0.50
-0.50
-1.50
-2.50
-3.50
-4.50
-10
-20
-0
5
3.
.5
-2
-0
.5
5
0.
2
4..5
5
.51.5
-20
0
20
X mm
ϖy =
∂u ∂w
−
∂z ∂x
40
15.00
14.00
13.00
12.00
11.00
10.00
9.00
8.00
7.00
6.00
5.00
4.00
0
-10
-20
-30
-30
-40
Vorticity distribution
(in-plane)
20
10
Y mm
0.5
1.5
-2.5 4.5
-
5
0.
-1.5
Y mm
3.0
11.0
1.5
-1.5
01.
.55
-3
.
-7 0
.0
9.0 7.0
9.0
11.0
0
-1.
-5.0
-1 .
0
--9
11.0
9.0
11.
0 1.0
.0
Y mm
3.
0
3.0
-3
.0
3.0 5.0
3.
0
-1
.0 5
.0
-1.0
Y mm
-5.0
7.
0
3.
0
3.
0
∂w ∂v
−
∂y ∂z
40
0
3.0
20
.5
0.5
.5
-0
3.0
10
.5
-0
5.0
1.0
-3
-2.5
Vorticity distribution
(Z-component)
5
1.07.0
-30
X mm
ϖx =
11.00
9.00
7.00
5.00
3.00
1.00
-1.00
-3.00
-5.00
-7.00
-9.00
-11.00
0
3.
.0
.0
-3
0
11
0
-7.
-20
.0
1.0
7.0
11.0
5.09.0-9-1.0.0
.0.0
-5-3
-40
-20
-5.0
7.0
-30
-10
-7.0 .0
-9.0-7
5.0
0
-1.0
1.0
-7.
-11.0
1.0
5.0
-20
5.0
-11
.0
-1 .0
-5
0
0
-3.
9.0
5.0
-10
.0
-5
-7.0
.0
-3
3.0
3.0
7.0
1.0
10
.5
-0
.
-0
.0
-1
-3.0
1.0
-1.0 -1
7.0
1.
0
11.0
0
11.00
9.00
7.00
5.00
3.00
1.00
-1.00
-3.00
-5.00
-7.00
-9.00
-11.00
5.0
.0
-5.0
-1
0
7.
10
20
Vorticity distribution
(Y-component)
20
-0.5
5.0
3.0
-7.0
1.
0
1.0
-1.5
-4.5
-1.0
1.0
.0
-3
5.0
9.0
7.0
0 0
-9.11.0.
--7
.0
-3.0
-1
20
Vorticity distribution
(X-component)
30
30
30
-1.0
-3.
0
-1.0
30
-0.5
1.0
-40
-20
0
20
X mm
∂v ∂u
ϖz = −
∂x ∂y
40
-40
-20
0
20
40
X mm
ϖ in − plane = ϖ x 2 + ϖ y 2
Measurement results downstream the lobed nozzle/mixer
grow up
40
30
30
Vorticity distribution
(in-plane)
20
-20
-20
-20
-30
-30
-30
Y mm
-40
-20
0
20
40
6.00
5.60
5.20
4.80
4.40
4.00
3.60
3.20
2.80
2.40
2.00
Y mm
-10
6.00
5.60
5.20 10
4.80
4.40
4.00 0
3.60
3.20
2.80 -10
2.40
2.00
0
Vorticity distribution
(in-plane)
20
10.00
9.00
8.00 10
7.00
6.00
5.00 0
4.00
3.00
2.00-10
10
broken down
40
30
Vorticity distribution
(in-plane)
20
Y mm
pinch-off
40
-40
-20
0
X mm
20
40
-40
-20
a. Z=20mm cross plane
(Z/D=0.50)
20
40
X mm
b. Z=40mm cross plane
(Z/D=1.0)
c. Z=60mm cross plane
(Z/D=1.5)
Evolution of Kelvin-Helmholtz Vortex Structures
Measured 3-D velocity vectors
dissipated
grow up
40
40
40
30
30
30
20
20
Streamwise Vortcitity
Streamwise Vortcitity
2.50
10
1.79
1.07
0.36
-0.36 0
-1.07
-1.79
-10
-2.50
-20
4.50
10
3.50
2.50
1.50
0.50 0
-0.50
-1.50
-10
-2.50
-3.50
-4.50
-20
-30
-30
-30
Y mm
Y mm
10
0
-10
-40
-40
-20
0
20
40
X mm
-40
60-40
2.50
1.79
1.07
0.36
-0.36
-1.07
-1.79
-2.50
-20
-20
0
20
X mm
a. Z=20mm cross plane
(Z/D=0.50)
Streamwise Vortcitity
Y mm
20
Iso-surface of velocity field
0
X mm
b. Z=40mm cross plane
(Z/D=1.0)
40
-40
60-40
-20
0
20
X mm
c. Z=60mm cross plane
(Z/D=1.5)
Evolution of Large-scale Streamwise Vortex Structures
40
60
Molecule-based flow diagnostic techniques ? Why!? How!?
• Issues associated with particle-based flow diagnostic techniques such as LDV, PIV, PDV and PIV:
• Measure the velocity or temperature of tracer particles, other than the working fluid directly.
• Flow tracking issues (particle size, density mismatch, …)
• Seeding issues (particles don’t always go where you need them)
• Thermal response of the tracer particles for temperature measurements.
•
Molecule-based techniques: Molecular Tagging Velocimetry (MTV)
• Instead of using tiny particles, specially-designed molecules are used as the tracers for flow diagnostics.
• Use pulsed laser beams to tag the molecular tracers premixed in the fluid flow.
• The tagged molecules can emit long-lived laser-induced fluorescence or phosphorescence.
• Take two images with known time delay after same pulsed laser excitation.
• Find the displacement vectors of the tagged molecules.
• Local velocity = displacement / time delay.
First image
(right after the laser pulse)
Second image
(imaged 3.5 ms later)
Derived velocity field (Bohl et al. 2002)
Molecular Tagging Thermometry (MTT) technique
Spectraphotometer Output vs Wavelength
According to quantum theory,
theory, the decay of phosphorescence
emission intensity (I
(Iem) follows an exponential law:
I em = I o e
− t /τ
= I i Cε Φ p e
Phosphorescence
4000
− t /τ
Io : Initial phosphorescence intensity:
intensity: Ii : the local incident laser intensity;
intensity;
C : concentration of dye;
dye;
ε : the absorption coefficient,
coefficient, temperaturetemperature-dependant;
dependant;
Φp: phosphorescence quantum yield, temperaturetemperature-dependant;
dependant;
τ : phosphorescence lifetime, which refers to the time when the intensity
drops to 37% (i.e. 1/e
temperature-dependant.
1/e) of the initial intensity (I
(I0), temperatureHeated cylinder
Relative intensity
•
5000
o
T = 32.0 C
o
T= 25.4 C
o
T= 19.7 C
o
T= 14.5 C
o
T = 10.2 C
o
T= 3.40 C
3000
2000
fluorescence
1000
0
200
300
400
500
600
700
800
Wavelength (nm)
-1
a. Phosphorescence
image (7ms after
laser pulse, exposure
time 1ms
0
o
Temperature C
1
28.00
27.75
27.50
27.25
27.00
26.75
26.50
26.25
26.00
25.75
25.50
25.25
25.00
24.75
24.50
24.25
X/D
2
b. Background
(Ii information)
3
4
5
6
-2
0
2
Y/D
4
6
Molecular Tagging Velocimetry and Thermometry (MTV&T)
• Lifetime imaging technique:
S2
= e −Δt /τ
S1
τ =
⇒
Δt
τ = τ (T )
ln( S / S )
2 1
⇒
T = T ( x, y )
Laser excitation pulse
Phosphorescence intensity
(
S1 = I i C ε Φ p 1 − e
− δ t /τ
)e
− to /τ
(
−δ t /τ
S2 = Ii Cε Φp 1− e
)e
−(to +Δt ) /τ
MTV&T technique
S1
S2
δt
δt
time
Δt
5
data
data
data
data
lifetime (ms)
4
set
set
set
set
4
3
2
1
(solution
(solution
(solution
(solution
Phosphorescence Lifetime
of 11-BrNp⋅Gβ-CD⋅ROH
molecule vs. Temperature
2
1
25
30
35
40
o
Temperature ( C)
45
ƒ The measured displacement of the
tagged molecules between the two
image acquisitions provides the
estimate of the flow velocity vector.
ƒ The intensity ratio of the two images is
used to derive the laser-induced
photoluminescence lifetime.
3)
2)
1)
1)
3
20
MTV images
50
ƒ Simultaneous temperature
measurement is used to achieve by
taking advantage of the temperature
dependence of photoluminescence
lifetime.
Measurement results in the wake of a heated cylinder
heated cylinder
heated cylinder
-1
0.026 m/s
0
O
Temperature ( C )
1
26.000
25.925
25.850
25.775
25.700
25.625
25.550
25.475
25.400
25.325
25.250
25.175
25.100
25.025
24.950
24.875
24.800
24.725
24.650
24.575
24.500
2
3
X/D
4
5
6
7
8
9
first image (1ms after laser pulse )
10
second image (6ms after laser pulse )
A. Tfluid = 24.0 °C , Tcylinder = 35.0 °C, Re=130, Gr=3300,
Gr=3300,
11
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
Y/D
Ri=0.19,
Ri=0.19, Str=0.157
Str=0.157
-1
0.026 m/s
0
O
Temperature ( C )
1
29.500
29.250
29.000
28.750
28.500
28.250
28.000
27.750
27.500
27.250
27.000
26.750
26.500
26.250
26.000
25.750
25.500
25.250
25.000
24.750
24.500
2
3
X/D
4
5
6
7
8
9
10
first image (1ms after laser pulse )
second image (6ms after laser pulse )
B. Tfluid = 24.0 °C , Tcylinder = 83.0 °C, Re=130, Gr=18200,
Gr=18200,
Ri=1.05,
Ri=1.05, Str=0.103
Str=0.103
11
-5
-4
-3
-2
-1
0
1
Y/D
2
3
4
5
6
7
Measurement Results of the MTV&T technique
-1
-1
O
Temperature ( C )
25.500
25.450
25.400
25.350
25.300
25.250
25.200
25.150
25.100
25.050
25.000
24.950
24.900
24.850
24.800
24.750
24.700
24.650
24.600
24.550
24.500
2
3
X/D
4
5
6
7
8
9
28.500
28.300
28.100
27.900
27.700
27.500
27.300
27.100
26.900
26.700
26.500
26.300
26.100
25.900
25.700
25.500
25.300
25.100
24.900
24.700
24.500
2
3
4
5
6
7
8
9
10
-4
-3
-2
-1
0
1
2
3
4
5
6
11
7
Y/D
Ri=1.05
1
3
4
5
6
7
8
9
10
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
11
7
-5
-4
-3
-2
-1
0
EnsembleEnsemble-averaged velocity and temperature distributions at different Richardson
Richardson levels
0
0.1
1
1
turbulent thermal flux
2
2
2
2
3
3
6
7
5
6
7
5
6
7
9
10
10
10
-3
-2
-1
0
1
Y/D
2
3
4
5
6
7
11
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
2
0.120
0.110
0.100
0.090
0.080
0.070
0.060
0.050
0.040
0.030
0.020
0.010
4
9
-4
0.1
2
9
-5
7
sqrt((u'T') +(v'T') )
8
11
6
3
8
8
5
turbulent thermal flux
2
2
0.120
0.110
0.100
0.090
0.080
0.070
0.060
0.050
0.040
0.030
0.020
0.010
4
X/D
X/D
5
4
sqrt( (u'T') +(v'T') )
sqrt((u'T') +(v'T') )
4
3
Ri=1.05
1
turbulent thermal flux
2
0.120
0.110
0.100
0.090
0.080
0.070
0.060
0.050
0.040
0.030
0.020
0.010
2
0
0.1
Ri=0.50
X/D
Ri=0.19
1
Y/D
-1
-1
0
30.000
29.725
29.450
29.175
28.900
28.625
28.350
28.075
27.800
27.525
27.250
26.975
26.700
26.425
26.150
25.875
25.600
25.325
25.050
24.775
24.500
2
Y/D
-1
O
Temperature ( C )
10
-5
0.026 m/s
0
O
Temperature ( C )
Ri=0.50
1
X/D
Ri=0.19
1
0.026 m/s
0
X/D
0
11
-1
0.026 m/s
11
-5
-4
-3
Y/D
Turbulent thermal flux distributions at different Richardson levels
levels
-2
-1
0
1
Y/D
2
3
4
5
6
7
Instantaneous, Quantitative Measurement of Molecular Mixing in Gaseous Flows
1
ƒ The effective phosphorescence quenching
by oxygen of molecular tracers such as
acetone and biacetyl is used to provide
“resolution-free” estimation of molecular
mixing in gaseous flows.
0.1
Relative intensity
ƒ Conventional Laser Induced Fluorescence
(LIF) technique tends to overpredict the
amount of molecularly mixed fluid due to
the limited-resolution of the CCD camera.
Relative intensity
1
with air
life time τ=6ns
0.01
Exponential fit
Experimental data
0.5
Oxygen free (with N2)
life time τ=13μs
0.2
0.1
0.001
20
30
40
50
60
Expontential fit
Experimental data
0
5
10
15
20
time delay (μs)
time delay (ns)
In nitrogen flow
(oxygen free)
In airflow
1.9
3.5
3.5
fraction of unmixed
acetone funmixed-acetone
3.5
fraction of total acetone
ftotal-acetone
0.95
3
0.90
0.85
0.80
0.75 2.5
0.70
0.65
0.60
0.55
2
0.50
0.45
0.40
0.35 1.5
0.30
0.25
0.20
1
0.15
0.10
0.05
0.00
0.5
Y/D
Y/D
2.5
2
1.5
1
0.5
-1
0
1
R(x)/D
2
fraction of mixed
acetone
zoom-in
window B
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Y/D
3
0.95
0.90 3
0.85
0.80
0.75 2.5
0.70
0.65
0.60
0.55 2
0.50
0.45
0.40
0.35 1.5
0.30
0.25
0.20
0.15 1
0.10
0.05
0.00
Ι
zoom-in
window A
0
1
R(x)/D
2 -1
fmixed
fun-mixed
ftotal
1.3
1.0
0.7
0.4
0.1
-0.05
-0.03
-0.01
0.01
0.03
ηmixed
1.6
fmixed
fun-mixed
ftotal
1.3
1.0
0.7
0.4
0
1
R(x)/D
2
0.1
0.20
0.22
0.24
0.26
0.28
R(x)/D
total concentration
distribution of the jet stream
(fluorescence image)
Unmixed portion of the jet
stream (phosphorescence
(phosphorescence
image with 1 μs delay)
delay)
0.05
R(x)/D
1.9
0.5
-1
ηmixed
1.6
ΙΙ
MolecularlyMolecularly-mixed portion
of the jet stream
MolecularlyMolecularly-mixed
efficiency at the interface
of the two streams
0.30
Micro-scale flows and micro-scale heat transfer in microfluidics
velocity
(m/s)
0
R
5
9. um
= 30
Re = 3
W
0.5
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10
8 m
4. u
= 30
e =3
W
Y/W
1
1.5
Hydraulic diameter of the
microchannel is 191 μm
2
2.5
135μm
~1 μm fluorescent particles
as the tracer for μ-PIV
330μm
0
1
2
3
X/W
Micro-PIV measurements of flows in a Y –shaped microchannel
Temperature
o
( C)
Wall
40
3.0
150
2.5
Electroosmotic Velocity
300μ
300μm
negatively charged
walls
(a). 0.5
ms
after
laser
pulse
Debye
layer on
the order
of 1nm
300µ
300µ
m
Wall
35
50
Velocity (mm/s)
Quartz walls
100
Spatial Location (μm)
Electrode
Velocity
0
Temperature
-50
-150
(b).
5ms
later
1.5
30
1.0
Temperature
0.5
25
-100
2.0
0
-0.5
0
Temperature 30
o
( C)
1
2
3
4
32
34
36
38
Velocity(mm/s)
Turn on electric field
5
40 20
-1.0
0
5
10
Micro-MTV&T measurements in an electroosmotic flow
15
20
Time (seconds)
25
30
35
Active Control of the Mixing Process at Low Reynolds Number
oscillation amplitude of
the actuator is 60µm
actuator
No excitation
f=2Hz
f=4Hz
f=6Hz
f=8Hz
f=10Hz
f=12 Hz
V = 10 mm/s
(water with dye )
V = 10 mm/s
(pure water)
5.0mm
f=14hz
f=16Hz
f=18Hz
f=20Hz
f=25Hz
f=30Hz
f=40 Hz
Quantum Dot Imaging for Thermofluid Diagnostics
1.2
(CdSe)ZnS quantum dot
Normalized fluorescence intensity
1.1
Normalized Fluorescence intensity
1.0
0.9
QD 4 (laser power 200mJ/pulse)
QD 4 (laser power 150mJ/pluse)
Flourescein (laser power 200mJ/pulse)
Fluorescein (laser power 150mJ/pulse)
Fluorescein ( laser pulser 100mJ/pulse)
Rhodamine B( laser power 200mJ/pluse)
Rhodamine B (Laser power 150mJ/pulse)
Rhodamine B (laser Power 100mJ/pulse)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
25
50
75
100
125
150
175
200
225
250
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
QD-3 (514nm)
QD-3 (488nm)
QD-3 (308nm)
5
10 15 20 25 30 35 40 45 50 55 60 65 70
Total enegy input from the exicitation laser (J)
o
Temperature ( C)
Photo-bleaching effect
Temperature sensitivity
C/Co
23.0
22.0
21.0
20.0
19.0
18.0
17.0
16.0
15.0
14.0
13.0
12.0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
50
1.2
QDQD-1
QD-3 QDQDQD-2 QDQD-4 1.1
1.0
0.9
0.8
emission
0.7
0.6
0.5
0.4
0.3
0.2
absorption
0.1
0
300 350 400 450 500 550 600 650 700
wavelength (nm)
40
Y mm
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Temperature
o
( C)
0
5.5nm
emission (relative intensity)
absorption (relative intensity)
2.3nm
60
30
20
10
1
0
10
20
30
40
50
X mm
Concentration measurements in
a pulsed jet flow
measurements mapping in
a stratified flow
Biological-inspired Airfoil and Wing Planform Designs
for Micro-Air-Vehicle (MAV) Application
Dragonfly wing
NASA LS(1)-0417
Flat plate
U m/s: -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
0
U m/s: -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
0
50
Y (mm)
Y (mm)
Y (mm)
100
100
100
150
150
150
0
50
100
150
200
X (mm)
Dragonfly wing
250
U m/s: -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
0
50
50
10.0 m/s
10.0 m/s
10.0 m/s
0
50
100
150
200
250
0
X (mm)
Flat plate
Angle of attack α=10o , Re=34,000
50
100
150
X (mm)
NASA LS(1)-0417
200
250