Shock wave-boundary layer interaction in a transitional flow over a backward-facing step

Conference paper (2019)

Authors

W. Hu Aerodynamics - Aerospace Engineering
S. Hickel Aerodynamics - Aerospace Engineering
B.W. van Oudheusden Aerodynamics - Aerospace Engineering
Research Group
Aerodynamics (Aerospace Engineering) (TU Delft)
Copyright: © 2019 W. Hu, S. Hickel, B.W. van Oudheusden
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Published Date

2019

Language

English

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Faculty

Aerospace Engineering

Department

Flow Physics and Technology

Research Group

Aerodynamics

Abstract

The unsteadiness of shock wave-boundary layer interactions is investigated in a transitional backward-facing step flow at Ma=1:7 and Red0 =13718 using large eddy simulation. The mean and instantaneous flow shows that the laminar inflow undergoes a laminar-to-turbulence transition in which Kelvin-Helmholtz vortices form, distort and eventually break down into small hairpin-like vortices. The interaction system features broadband frequency oscillations in a range f d0=u¥ = 0:03 _ 0:23 based on the spectral and statistical analysis. The results of dynamic mode decomposition indicate that the medium-frequency motions centered at f d0=u¥ = 0:06 are related to the shock winkling and the shedding of large coherent vortices, while the lower (centered at f d0=u¥ _ 0:01) and higher ( f d0=u¥ _ 0:1) frequency unsteadiness is associated with the periodical dilatation and shrinking of separation system and the convection of upstream K-H vortices respectively.