Numerical Study on Evolution Characteristics of Vortices in Supersonic Mixing Layers

摘要

Vortices inside mixing layers impose remarkable aero-opticalrndistortions on a beam even at moderate subsonic speeds. However, withrnknowledge about vortices evolution in this mixing layer flow field,rnespecially for evolution characteristics of vortices in supersonic mixingrnlayer flow field is limited because the supersonic flow has very high speed.rnIn this study, the large eddy simulation (LES) was used to simulate thernsupersonic mixing layer flow field. The growth rate of supersonic mixingrnlayer and site of vortex rolling up acted as two evaluation parameters tornquantitatively investigate the evolution characteristics of vortices inrnsupersonic mixing layers. Subsequently, three suits of cases, in which therncompressibility of flow field, initially normal disturbance, and compositionsrnof the two incoming streams making up a supersonic mixing layer wererntaken into account, were performed to investigate the evolutionrncharacteristics of vortices in supersonic mixing layer in detail. The resultsrnindicated that the evolution characteristics of vortices were obviouslyrnaffected by the compressibility of flow field, initially normal disturbance,rnand compositions of the two incoming streams. Finally, several conclusionsrndrawn from this study were presented.