Abstract
Oscillatory phenomena of an underexpanded jet which impinges on a flat plate are discussed in this paper. We focus the effect of the oscillation on the motion of the separation bubble which is formed near the plate. In this study, the flow field is visualized by the shadowgraph method and the frequency of the oscillation is measured. Three dimensional Euler equations are solved using symmetric TVD scheme. A comparatively strong shock (plate shock) is experimentally and numerically visualized in front of the plate. The location and the configuration of the shock are found to affect the flow condition in the region between the plate shock and the plate. In addition, the details of the motion of the plate shock are numerically analyzed. As a result, it is found that the separation bubble is generated under certain conditions and the oscillation of the jet causes the transformation of the separation bubble.
