Shock-shock interactions for a double wedge configuration in different gases

A kinetic, particle method has been used to model laminar shock-shock interactions of hypersonic flow over a 30/55-deg double-wedge configuration studied in the Hypervelocity Expansion Tube (HET) facility. The current study focuses on the investigation of Mach 7 nitrogen, air and argon flows for a stagnation enthalpy of 8.0 MJ/kg, conditions where thermochemical nonequilibrium is present. The simulations are found to reproduce many of the classic features related to Edney Type V strong shock interactions that include the attached, oblique shock formed over the first wedge, the detached bow shock from the second wedge, the strong separation zone, and the separation and reattachment shocks that cause complex features such as the triple point. As reported earlier,¹ it was found that a full threedimensional model was required to simulate the heat flux and transient behavior of the nitrogen flow. In contrast, preliminary 2-D results of a reacting air flow case seem to indicate that the size of the separation length and the time required to reach steady state is much less than was found for the 2-D nitrogen flow model and comparison with measured heat fluxes and time-dependent shock profiles for air are in reasonable agreement. Lastly, to understand the effects of the internal modes on the shock structure, argon flow is also studied.