Numerical study of shock interference patterns for nonequilibrium gas flows with thermal nonequilibrium and finite-rate chemistry

This work investigates shock interaction mechanisms in inviscid hypervelocity gas flows over double-wedge geometries using computational fluid dynamics. The SU2 CFD solver has been coupled to the Mutation++ library to simulate these interaction mechanisms for different gas mixtures accounting for thermochemical nonequilibrium. A systematic numerical study is performed to evaluate how shock interference patterns differ from Edney’s classification when air and CO2 mixtures are considered. Moreover, the impact of varying the freestream temperature is analysed. Results show that, for a freestream temperature of 57 K, a Type V nine-shock configuration and a Type VI-V transition is identified for air and CO2 flows, respectively. For a freestream temperature of 300 K, the same Type VI-V transition is obtained for the CO2 flow with a slightly different shape, whereas a Type V six-shock configuration is obtained for air. It is concluded that increasing the freestream temperature from 57 K to 300 K has more impact on the extent of thermochemical nonequilibrium of an air flow than of a CO2 flow, and consequently on the resulting interaction patterns. Moreover, thermal nonequilibrium is shown to be overall stronger for air than for CO2.