Study of Shock Boundary Layer Interaction using a Modified k-w Model Based on Estimated Shock Strength

Abstract

High-speed flows, such as those seen in scramjet engines, and rocket nozzles, are associated with complicated flow patterns such as shock boundary layer interaction (SBLI), which result in excessive vehicle surface heating and flow separation and reattachment. Engineering predictions of SBLI flows rely on Reynolds-averaged Navier-Stokes (RANS) methods. The turbulence models used in RANS often underpredict flow separation and overpredict surface heat flux. The flow properties change drastically across a shock wave, and so does the turbulent kinetic energy (TKE). Most turbulence models are limited in predicting the amplification of TKE at a shock, which depends on the strength of the shock. In this work, we use a recently developed shock function that computes the local shock strength (in terms of the density ratio) in situ with the flow field computation. The shock-unsteadiness (SU) modified k-w model, based on the accurate estimation of shock strength and shock location, is used to study SBLI flows at supersonic and hypersonic Mach numbers. The SU k-w model is developed based on the physics of shock-turbulence interaction and has been shown to improve SBLI prediction. Of particular interest is the effect of different non-adiabatic wall conditions, and the variation of the separation bubble size with shock strength. Results are compared with existing experimental and direct numerical simulation data.