Three-dimensional evolution of large-scale vortices in supersonic flow

The supersonic large-scale vortices generated by a streamwise vortex generator were investigated experimentally using the nanoparticle-based planar laser scattering method, with the emphasis on the entrainment and mixing characteristics in supersonic mixing layer. The spanwise coherent structures originated from the K-H instability grew up along with the vortex pairing process, which are able to exist in far field downstream of trailing edge. The large-scale streamwise vortex shed from the generator plays a major role in entraining the surrounding fluid from both sides of interface into mixing zone. Meanwhile, through the interaction with spanwise vortices, the streamwise vortex breaks up into the small-scale structures for molecular mixing. Moreover, the T-shaped structures and secondary K-H vortices are shown to be the usual topological structures in small-scale turbulence transport.