The influence of wall and shock curvature on shock reflection processes

The paper deals with the transition conditions from regular to irregular two-dimensional shock wave reflection at a convex curved obstacle in air and with the subsequent modes of irregular reflection determined by these conditions. It is shown that the slope of the reflected shock at the termination of regular reflection is different from that of the starting irregular reflection leading to a kink. This can be considered as the merging of two shocks with unequal slopes, thus producing the second Mach shock and the second slip line. Such a shock pattern is known as double Mach reflection. Simple Mach reflection is shown to be an exceptional case. The analysis is performed using visualized shock tube experiments, piezo-electric pressure measurements and the von Neumann Theories as an approximate theory and heuristic tool. (EMI)