Transverse injection from circular and elliptic nozzles into a supersonic crossflow

An investigation of sonic transverse injection from circular and elliptic n ozzles into a supersonic crossflow using planar Rayleigh/Mie scattering is reported. Instantaneous images allow examination of the structural details, whereas ensemble-averaged images provide transverse penetration and latera l spread data for each jet, Standard deviation images produce information r egarding the large-scale mixing/entrainment and reveal the mixing zones, Re sults show a highly three-dimensional near-field interaction dominated by s hear-layer eddies and a counterrotating, vortex pair Ensemble-averaged resu lts show that the elliptic jet spreads more rapidly in the lateral directio n than the circular jet, confirming that an axis-switching phenomenon is pr esent, Near-field transverse penetration data collapse well with low-speed scaling conventions; however, the jet produced by the elliptic nozzle suffe rs a 20% reduction in penetration compared to the circular jet. Compressibi lity level does not play a significant role in the average penetration or s pread of these jets, although it strongly affects the mixing/entrainment an d large-scale structure. Analysis of mixing potential from the standard dev iation images indicates that the low and High convective Mach number M-c in jection cases are significantly different; low M-c injection yields better large-scale mixing potential than high M-c injection regardless of the inje ctor geometry.