Observations of the initial stages of the Mach reflection process

Abstract

The initial stages of single, complex and double Mach reflection of incident shocks with Mach numbers of approximately 1.38 and 2.65 have been observed on wedges with angles ranging from 23° to 48°. At the smaller wedge angles no delay in the initiation of Mach reflection could be observed, to within ± 200 mean free paths of the ambient gas (γ). At larger wedge angles close to those for transition between regular and Mach reflection, both single and double Mach reflection were delayed by distances in the order of 10,000 γ. In the case of double Mach reflection, the reflection appeared to pass in sequence from regular to single, to complex and finally to double Mach reflection. Beyond distances in the order of 100,000 γ, the Mach reflections had become self similar and the trajectories of the triple points intersected the leading edge of the wedge.