Reflections of Shock Waves in Unsteady Flow

Abstract

The reflection of shock waves in unsteady flow is more complicated than that in steady and pseudosteady flows. Figure 9.1 illustrates three different types of unsteady reflections. When an incident shock I propagating from left to right collides with a convex half cylinder, the transition process of reflections is from the head- on collision, through regular reflection, to Mach reflection (Fig. 9.1a). When an incident shock I strikes a concave half cylinder, an opposite transition process takes place, i.e., from Mach reflection to regular reflection (Fig. 9.1b). In both cases the incident shock Mach number remains constant and only the wedge angles θ _θw change. Figure 9.lc shows that a spherical shock is reflected on a plane surface, in which both the incident shock Mach number and the reflected wedge angle decrease and the transition from regular to Mach reflections takes place.