A study of compressible mixing layers using filtered Rayleigh scattering

High Reynolds number compressible planar free shear layers were studied using a planar laser visualization technique. Two convective Mach numbers, M(c) = 0.51 and 0.86, were studied in the developing and fully developed regions. The structures in the M(c) = 0.51 case were characterized by 2D core and roller regions, similar to subsonic shear layers. Also for the M(c) = 0.51 case, plan views in the developing region showed the existence of streamwise streaks, possibly indicating the presence of organized streamwise vorticity. The M(c) = 0.86 flow was much less organized than the lower convective Mach number case and highly three dimensional.