Large Eddy Simulation of Shock Wave/Boundary Layer Interaction

Large-Eddy Simulation (LES) is used to simulate the compressible flat plate boundary layer with a Reynolds number up to 5×105. Numerical examples include shock wave/boundary layer interaction and boundary layer transition, aimed at future application to analysis of transonic fan/compressor cascades. The present LES code uses the hybrid compact/WENO scheme for spatial discretization, and the compact diagonalized implicit scheme for time integration. The present code successfully predicted the bypass transition of the subsonic boundary layer. For the supersonic turbulent boundary layer, mean and fluctuation velocity profiles of the attached boundary, as well as the evolution of the friction coefficient and the displacement thickness both upstream and downstream of the separation region are all in good agreement with the experiments. In the simulation of the shock wave/laminar boundary layer interaction, the dependence of the transition upon the strength of the shock wave is reproduced qualitatively. Span-wise disturbance is observed in the separation region, and the disturbance keeps growing when the shock wave is strong. However, it decays at the region between the incident shock wave and the reattachment of the boundary layer, for the weaker incident shock wave. These numerical examples show that LES can predict the behavior of the boundary layer including transition and shock wave interaction, which are poorly managed by the conventional Reynolds-Averaged Navier-Stokes approach. However, more effort is required before achieving quantitative agreement.