Analysis of acoustic wave from supersonic jets impinging to an inclined flat Plate

For the prediction and reduction of acoustic loading of launch vehicle at lift-off, acoustic wave radiated from ideally-expanded supersonic cold jets impinging to an 45-degree-inclined flat-plate, representative of a flame deflector, located 5D downstream from the nozzle exit is investigated numerically with the help of the experimental work. It turns out that dominant noise source is classified into three types: (i) the Mach wave radiation from free jet before the impingement, (ii) the acoustic wave generated from the impingement region, and (iii) another Mach wave radiation from supersonic wall jet after the impingement. Those features are clearly observed by applying the Proper Orthogonal Decomposition (POD) analysis to the numerical results. Comparing with the experimental result conducted in this study, prediction accuracy of 5 dB in OASPL is obtained in the current numerical simulation.