Geometric criterion for RR↔MR transition in hypersonic double-wedge flows

In a previous research article [Z. M. Hu et al., Phys. Fluids 21, 011701 (2009)], an overall Mach reflection (oMR) configuration with double inverse Mach reflection patterns was computationally confirmed when a double-wedge geometry interacts with a hypersonic flow. Extended computations are conducted in this paper and compared to analytical solutions based on the classical two- and three-shock theories. A geometric criterion is proposed for the transition between regular reflection and Mach reflection occurring inside the parameter space where a type V interaction of shock wave presents in hypersonic double-wedge flows. An oMR solution is allowed by the geometric criterion, while it is theoretically inadmissible. In the vicinity of symmetric condition, regular to Mach reflection transition can also be triggered prior to the theoretical criterion by disturbance generated by a slight increase in the second wedge angle.