Oscillation of Nearly Circular Shock Waves

Abstract

Oscillation modes of nearly circular shock waves in supersonic radial flow were investigated both theoretically and experimentally. The shock waves deformed from circular shape were obtained by the asymmetric back pressure produced by down-stream obstacles. Oscillation modes of the shock waves were investigated by means of statical study of the phase function and mean coherence in each static mode. The oscillation consisted of mode 0 and the same mode as the original static shape. The frequency of each static mode depended on the deformation from the real circle.