The effect of jet exit pressure ratio on a jet in cross flow

An experimental investigation of the effect of jet exit pressure ratio on a jet in supersonic cross flow has been undertaken. The flow characteristics of four jets of differing exit pressure ratio are investigated for constant momentum ratio and cross flow condition. Surface flow visualisation is used to investigate the footprint and blockage caused by the injectant jet, while schlieren and shadowgraph photography are implemented to explore the shock structure and jet penetration properties. Preliminary results show a monotonic decrease in the size and strength of the jet shock structure as the pressure ratio is reduced, with a closely pressure match state being achieved at the lowest exit pressure ratio tested. The reduction of the jet shock structure is accompanied by a reduction in the size of the bow shock and its stand-off distance from the jet. Despite the significant differences in mean shock structure the penetration achieved by each jet tested appears to be similar.