Numerical Study on Evolution Characteristics of Vortices in Supersonic Mixing Layers

Abstract

Vortices inside mixing layers impose remarkable aero-optical distortions on a beam even at moderate subsonic speeds. However, with knowledge about vortices evolution in this mixing layer flow field, especially for evolution characteristics of vortices in supersonic mixing layer flow field is limited because the supersonic flow has very high speed. In this study, the large eddy simulation (LES) was used to simulate the supersonic mixing layer flow field. The growth rate of supersonic mixing layer and site of vortex rolling up acted as two evaluation parameters to quantitatively investigate the evolution characteristics of vortices in supersonic mixing layers. Subsequently, three suits of cases, in which the compressibility of flow field, initially normal disturbance, and compositions of the two incoming streams making up a supersonic mixing layer were taken into account, were performed to investigate the evolution characteristics of vortices in supersonic mixing layer in detail. The results indicated that the evolution characteristics of vortices were obviously affected by the compressibility of flow field, initially normal disturbance, and compositions of the two incoming streams. Finally, several conclusions drawn from this study were presented.