Structural responses of the supersonic turbulent boundary layer to the expansions induced by a convex wall and a ramp are experimentally investigated. Relaminarization of part of the turbulent boundary layer in the near wall region is clearly visualized, which has been seldom presented before. The relaminarized layers formed over two test models are different. While a thicker relaminarized layer is observed for the ramp, a longer lasting layer is noticed for the convex wall. The structure angle is found to be increased by the expansions. Increases of turbulence scale and boundary layer thickness are observed. The contribution of the bulk dilatation to the boundary layer growth is stronger than that of the centrifugal force.

1.
M. M.
Gibson
,
C. A.
Verriopoulos
, and
N. S.
Vlachos
, “
Turbulent boundary layer on a mildly curved convex surface, Part 1: Mean flow and turbulence measurements
,”
Exp. Fluids
2
,
17
(
1984
).
2.
M. M.
Gibson
and
C. A.
Verriopoulos
, “
Turbulent boundary layer on a mildly curved convex surface, Part 2: Temperature field measurements
,”
Exp. Fluids
2
,
73
(
1984
).
3.
K. C.
Muck
,
H.
Hoffmann
, and
P.
Bradshaw
, “
The effect of convex surface curvature on turbulent boundary layers
,”
J. Fluid Mech.
161
,
347
(
1985
).
4.
J. J.
Luker
,
R. D. W.
Bowersox
, and
T. A.
Buter
, “
Influence of curvature-driven favorable pressure gradient on supersonic turbulent boundary layer
,”
AIAA J.
38
,
1351
(
2000
).
5.
J. C.
Gillis
and
J. P.
Johnston
, “
Turbulent boundary-layer flow and structure on a convex wall and its redevelopment on a flat wall
,”
J. Fluid Mech.
135
,
123
(
1983
).
6.
S. A.
Arnette
,
M.
Samimy
, and
G. S.
Elliott
, “
The effects of expansion on the turbulence structure of compressible boundary layers
,”
J. Fluid Mech.
367
,
67
(
1998
).
7.
J. P.
Dussauge
and
J.
Gaviglio
, “
The rapid expansion of a supersonic turbulent flow: role of bulk dilatation
,”
J. Fluid Mech.
174
,
81
(
1987
).
8.
S. A.
Arnette
,
M.
Samimy
, and
G. S.
Elliott
, “
Structure of supersonic turbulent boundary layer after expansion regions
,”
AIAA J.
33
,
430
(
1995
).
9.
N. R.
Tichenor
,
R. A.
Humble
, and
R. D. W.
Bowersox
, “
Response of a hypersonic turbulent boundary layer to favourable pressure gradients
,”
J. Fluid Mech.
722
,
187
(
2013
).
10.
R.
Mukund
,
R.
Viswanath
,
R.
Narasimha
,
A.
Prabhu
, and
J. D.
Crouch
, “
Relaminarization in highly favourable pressure gradients on a convex surface
,”
J. Fluid Mech.
566
,
97
(
2006
).
11.
P.
Bradshaw
, Effects of streamline curvature on turbulent flow, AGARDograph No. 169,
Report No. AD0768316
,
1973
.
12.
P.
Bradshaw
, “
The effect of mean compression or dilatation on the turbulence structure of supersonic boundary layers
,”
J. Fluid Mech.
63
,
449
(
1974
).
13.
Y. X.
Zhao
,
S. H.
Yi
,
L. F.
Tian
, and
Z. Y.
Cheng
, “
Supersonic flow imaging via nanoparticles
,”
Sci. China Ser. E-Tech. Sci.
52
,
3640
(
2009
).
14.
Q. C.
Wang
,
Z. G.
Wang
,
J.
Lei
, and
J. H.
Feng
, “
Characteristics of mixing enhanced by streamwise vortices in supersonic flow
,”
Appl. Phys. Lett.
103
,
144102
(
2013
).
15.
R. A.
Humble
,
S. J.
Peltier
, and
R. D. W.
Bowersox
, “
Visualization of the structural response of a hypersonic turbulent boundary layer to convex curvature
,”
Phys. Fluids
24
,
106103
(
2012
).
16.
Q. C.
Wang
and
Z. G.
Wang
, “
Structural characteristics of the supersonic turbulent boundary layer subjected to concave curvature
,”
Appl. Phys. Lett.
108
,
114102
(
2016
).
17.
J.
Poggie
,
P. J.
Erbland
,
A. J.
Smits
, and
R. B.
Miles
, “
Quantitative visualization of compressible turbulent shear flows using condensate-enhanced Rayleigh scattering
,”
Exp. Fluids
37
,
438
(
2004
).
18.
M. J.
Ringuette
,
P.
Bookey
,
C.
Wyckham
, and
A. J.
Smits
, “
Experimental study of a Mach 3 compression ramp interaction at Re
=
2400
,”
AIAA J.
47
,
373
(
2009
).
You do not currently have access to this content.