The influence of large scale roughness on a turbulent hypersonic boundary layer approaching a compression corner

1995 ◽  
Author(s):  
H Babinsky ◽  
J Edwards
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Hypersonic Boundary Layer ◽  
Compression Corner ◽  
Scale Roughness

Hypersonic compression corner flow with large separated regions

2019 ◽  
Vol 877 ◽  
pp. 471-494 ◽  
Author(s):  
Sudhir L. Gai ◽  
Amna Khraibut
Keyword(s):  
Large Scale ◽  
Asymptotic Theory ◽  
Reverse Flow ◽  
Boundary Layer Separation ◽  
Recirculation Region ◽  
Hypersonic Boundary Layer ◽  
Temperature Ratio ◽  
Scale Separation ◽  
Compression Corner ◽  
Corner Flow

The structure of large-scale hypersonic boundary layer separation and reattachment is studied numerically using a flat plate/compression corner geometry. Apart from verifying the large scale separation characteristics in hypersonic flow, a detailed discussion of secondary separation and fragmentation into multiple vortices embedded within the main recirculation region is presented. The unique relation between the second minimum in shear stress and the scaled angle is highlighted in the context of the reverse flow singularity of Smith (Proc. R. Soc. Lond. A, vol. A420, 1988, pp. 21–52) and it appears that for a small wall temperature ratio, such a singularity is unlikely. It is shown that the size of the separation can be estimated in terms of Burggraf’s expression based on asymptotic theory.

Comparative effects of vortex generators on Ahmed’s squareback and minivan car models

2017 ◽  
Vol 231 (9) ◽  
pp. 1287-1293 ◽  
Author(s):  
Antoine Evrard ◽  
Olivier Cadot ◽  
Christophe Sicot ◽  
Vincent Herbert ◽  
Denis Ricot ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Vortex Generator ◽  
Vortex Generators ◽  
Longitudinal Vortices ◽  
Car Model ◽  
Bubble Length ◽  
Base Drag ◽  
Scale Roughness ◽  
Ahmed Body

This work aims to evaluate the base suction and drag modifications caused by a boundary layer manipulation due to large scale roughness prior its salient separation. A real car model, a Peugeot 208, and a squareback Ahmed body are both tested and compared in a scale 1 wind tunnel at 120 km/h with road effect and rotating wheels. The roughnesses are vortex generators placed in the boundary layer that develops on the roof of the model. They produce longitudinal vortices in the free shear. Two types of vortex generators are used, wall mounted cylinders for weak disturbances and inclined blades for stronger disturbances. It is found that whatever the vehicle is, the drag is always increased. For the squareback Ahmed body, the base suction is decreased with similar magnitudes for both vortex generators showing a beneficial effect of the vortex generator on the base drag. On the contrary, the base suction is always increased for the real car whatever the vortex generators used. In that case the effects of magnitude depends on the vortex generator types. While the cylinders degrade slightly the base suction with almost no modification in the wake, the blades are able to reduce considerably the bubble length causing a huge increase in drag, lift and base suction.

Effect of angle of attack on hypersonic boundary-layer stability

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 464-470 ◽  
Author(s):  
Glen P. Doggett ◽  
Ndaona Chokani ◽  
Stephen P. Wilkinson
Keyword(s):  
Boundary Layer ◽  
Angle Of Attack ◽  
Boundary Layer Stability ◽  
Hypersonic Boundary Layer

scholarly journals Shock-induced heating and transition to turbulence in a hypersonic boundary layer

2020 ◽  
Vol 909 ◽  
Author(s):  
Lin Fu ◽  
Michael Karp ◽  
Sanjeeb T. Bose ◽  
Parviz Moin ◽  
Javier Urzay
Keyword(s):  
Boundary Layer ◽  
Transition To Turbulence ◽  
Hypersonic Boundary Layer

Abstract

scholarly journals Nonlinear interactions in a hypersonic boundary layer

AIP Advances ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 035104
Author(s):  
Chuanhong Zhang ◽  
Zhiwei Shi
Keyword(s):  
Boundary Layer ◽  
Hypersonic Boundary Layer ◽  
Nonlinear Interactions
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