LES Study on Mechanism of Reduction of Shock Induced Flow Separation by MVG

Shock-boundary layer interaction (SBLI) is a kind of problem which is frequently met in supersonic engine inlet flow and external flow. A detail study on mechanism of reduction of shock induced flow separation by MVG is carried out by high order implicit large eddy simulation (LES). To generate the fully developed turbulent flow, a series of turbulent profiles are given by previous DNS simulation results. The mechanism of reduction of shock induced flow separation was originally considered as a result of plump velocity profile caused by turbulent kinetic energy. It was acclaimed that turbulent flow has so stronger kinetic energy that the velocity profile is changed to be plump, which lead to reduction of shock induced flow separation. However, according to our detail study in this paper, the shock wave breaks down when ring-like vortices generated by MVG are passing through it, while the vortex structure never breaks down and is even little influenced. Therefore, the flow separation induced by shock is reduced by break-down of shock wave, not plump velocity profile. More details of the investigation on the mechanism are reported in this paper.