Cumulation effect upon the interaction between a shock and a local gas region with elevated or lowered density

The interaction between a plane normal shock and ellipsoidal regions of elevated or lowered density in an ideal perfect gas is investigated. Qualitatively different interaction patterns, regular and irregular, are found to exist. It is noted that as a result of the irregular interaction a complicated flow incorporating refracted shocks, tangential discontinuities, and vortices is formed. The effect of shock cumulation on the axis of symmetry occurring outside or inside a gas inhomogeneity of both lowered and elevated density is studied. The qualitative and quantitative influence of the inhomogeneity shape on the cumulation effect is investigated.