This grant will support experimental research on the effect of compressibility on mixing between co-flowing streams. Convective Mach numbers in the mixing layers will vary from low to as high as 3. The geometrical features and their evolution and interactions will be studied, with optical diagnostics including planar Rayleigh scattering and planar laser-induced flurescence. Mixing between two streams is known to be degraded at high relative flow velocites, but the reason is not yet understood. Understanding and control of high speed mixing layers is of crucial importance in combustion and propulsion systems.//
