Flow structures of strong interaction between an oblique shock wave and a supersonic streamwise vortex

Abstract

The oblique shock/vortex interaction (OSVI) is numerically investigated based on the large-eddy simulation method. A Mach interaction between separated shock and incident shock can be found when the pressure at the recirculation region reaches a certain level. Based on the idea of spatial–temporal correlation, which considers the three-dimensional steady interaction as a two-dimensional unsteady problem, a qualitative analysis is conducted to explain complicated three-dimensional shock structures. The interaction can be regarded as a combination of the following events: the interaction between circular shock and normal shock, the reflection of shock wave on a subsonic interface, and the interaction between secondary circular shock and other shock structures. Though the original vortex has broken down, a pair of streamwise vortices can be observed in the downstream flow field, the formation of which is associated with the split of the recirculation region. Moreover, the recirculation region is found to act as a solid body, which means that the flow angle along a splitting curve can reflect the splitting speed. Three stages can be identified according to the change process of the flow angle along the splitting curve, which are rapid growth, linear growth, and decrease stages. Inspired by the studies on the shock-induced boundary layer separation, the flow field of the strong OSVI with a regular interaction is modeled to predict the initial flow angle of the splitting point which is the foundation of the study on other stages. The interaction type between separated shock and incident shock can also be judged according to this approach.