Multimedia files – 12/13
Nonlinear wave packets
in swept-wing boundary layer
Contents:
1. Late stage of laminar-turbulent transition on a flat plate
2. Swept-wing boundary layer
3. Test model
4. Automated measurements
5. Controlled excitation of the boundary-layer disturbances
6. Wave packet in 2D boundary layer
7. Wave packet in 3D boundary layer
8. Summary
9. Relevant publications
1. Late stage of laminar-turbulent transition
on a flat plate
Flow visualization by W.S. Saric, V.V., Kozlov,
V.Ya. Levchenko (1984)
Direct numerical simulation (Rist et al. 1998)
of laboratory experiments (Kachanov 1994)
K-regime of transition in a flat-plate boundary layer
(see page of notes)
2. Swept-wing boundary layer
External streamline (left) and the mean flow in the boundary layer (right)
(see page of notes)
3. Test model
General view (left) and the sketch (right) of experimental model
(see page of notes)
4. Automated measurements
Traversing system (left) and the scheme (right) of automated triggered
hot-wire measurements
(see page of notes)
5. Controlled excitation of the boundary-layer disturbances
C
X
Z'
Excitation point
0.4 C
Qo
Generation of the boundary layer perturbations at the model surface
(see page of notes)
6. Wave packet in 2D boundary layer (I)
0- sweep
Click to play
A video clip by Chernoray V.G., Kozlov V.V., Löfdahl L., Pratt P. (2006)
6. Wave packet in 2D boundary layer (II)
0- sweep
y/
X = 0.48
y/
y/
0.72
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
5
0
-40
5
0
-40
y/
0.66
5
0
-40
5
0
-40
y/
0.6
0.54
5
0
-40
*
z c , mm
Isosurfaces of the streamwise velocity component at zero sweep angle where dark and
light half-tones represent positive and negative values of the disturbance amplitude,
respectively (left); isolines of the mean velocity distortion for 25, 50 and 75 % of Q0
levels and the contours of velocity fluctuations urms with step equal to 10 % of Q0 for the
cross sections at x/c = 0.48, 0.54, 0.60, 0.66 and 0.72 (from bottom to top) (right)
7. Wave packet in 3D boundary layer (I)
30- sweep
Click to play
A video clip by Chernoray V.G., Kozlov V.V., Löfdahl L., Pratt P. (2006)
7. Wave packet in 3D boundary layer (II)
30- sweep
y/
X = 0.5
y/
y/
0.65
0.71
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
5
0
-40
5
0
-40
y/
0.6
5
0
-40
5
0
-40
y/
0.55
5
0
-40
*
z c , mm
Isosurfaces of the streamwise velocity component at 30° sweep angle where dark and
light half-tones represent positive and negative values of the disturbance amplitude,
respectively (left); isolines of the mean velocity distortion for 25, 50 and 75 % of Q0
levels and the contours of velocity fluctuations urms with step equal to 10 % of Q0 for the
cross sections at x/c = 0.48, 0.54, 0.60, 0.66 and 0.72 (from bottom to top) (right)
7. Wave packet in 3D boundary layer (III)
45- sweep
Click to play
A video clip by Chernoray V.G., Kozlov V.V., Löfdahl L., Pratt P. (2006)
7. Wave packet in 3D boundary layer (IV)
45- sweep
y/
X = 0.49
y/
y/
0.68
0.74
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
-30
-20
-10
0
10
20
30
40
5
0
-40
5
0
-40
y/
0.62
5
0
-40
5
0
-40
y/
0.55
5
0
-40
*
z c , mm
Isosurfaces of the streamwise velocity component at 45° sweep angle where dark and
light half-tones represent positive and negative values of the disturbance amplitude,
respectively (left); isolines of the mean velocity distortion for 25, 50 and 75 % of Q0
levels and the contours of velocity fluctuations urms with step equal to 10 % of Q0 for the
cross sections at x/c = 0.48, 0.54, 0.60, 0.66 and 0.72 (from bottom to top) (right)
8. Summary
0 30
45
Localized boundary layer
distrubances at different
sweep angle
(see page of notes)
9. Relevant publications
Bake S., Meyer D.G.W., Rist U. (2002) Turbulence mechanism in Klebanoff transition: a quantitative comparison
of experiment and direct numerical simulation. J. Fluid Mech., 459, 217–243.
Chernoray V.G., Bakchinov A.A., Kozlov V.V., Löfdahl L. (2001) Experimental study of the K-regime of
breakdown in straight and swept wing boundary layers. Phys. Fluids, 13(7), 2129–2132.
Chernoray V.G., Dovgal A.V., Kozlov V.V., Löfdahl L. (2005) Experiments on secondary instability of streamwise
vortices in a swept wing boundary layer. J. Fluid Mech., 534, 295–325.
Chernoray V.G., Kozlov V.V., Löfdahl L., Pratt P. (2006) Hot-wire anemometry visualization of the complex
turbulent flows. Thermophysics and Aeromechanics, 13(2), 229–237.
Chernoray V., Kozlov V., Pratt P., Löfdahl, L. (2005) Hot wire visualizations of breakdown to turbulence in
complex flows. In Proc. EUCASS Conf. Moscow, Russia, 2.11–2.12.
Kachanov Y.S. (1994) Physical mechanisms of laminar-boundary-layer transition. Annu. Rev. Fluid Mech., 26,
411–482.
Kachanov Y.S., Kozlov V.V., Levchenko V.Ya. (1978) Nonlinear development of a wave in a boundary layer. Izv.
Akad. Nauk SSSR, Mekh. Zhidk. Gaza, 5, 85–94 (in Russian). Transl. Fluid. Dyn., 12, 383–390.
Klebanoff P.S., Tidstrom K.D., Sargent L.M. (1962) The three-dimensional nature of boundary layer instability. J.
Fluid Mech., 12, 1–34.
Litvinenko Yu.A., Grek G.R., Kozlov V.V., Löfdahl L., Chernoray V.G. (2004) An experimental study of varicose
instability of streaky structure in a boundary layer of swept wing. Thermophysics and Aeromechanics, 11(1),
1–11.
Reed H.L., Saric W.S. (1989) Stability of three-dimensional boundary layers. Annu. Rev. Fluid Mech., 21,
235–
284.
Rist U., Müller K., Wagner S. (1998) Visualisation of late-stage transitional structures in numerical data using
vortex identification and feature extraction. In G.M. Carlomango and I. Grant (Eds.), Eighth Intern. Symp. on
Flow Visualisation. Sorrento (Paper 109).
Saric W., Kozlov V., Levchenko V. (1984) Forced and unforced subharmonic resonance in boundary layer
transition. AIAA Paper 84–0007.