振动激发对激波反射的影响

Steady shock reflections include regular reflection and Mach reflection, which can transit to each other under critical conditions. High-temperature gas effect is inevitable in hypersonic shock reflections. As temperature increases, the vibration excitation of air molecules comes first. Theoretical analysis and quantitative calculation are conducted to study the effects of vibration excitation on shock reflections and the transitions between regular reflection and Mach refection. A thermodynamic model for air with vibration excitation is presented and then compared with the calorically perfect gas model. The influences of vibration excitation on shock relations, on the flow fields in regular reflection and Mach reflection, and on the transition criteria between them are analyzed. The results show that vibration excitation may enlarge the overall profile of the shock polar as compared with the shock polar in the calorically perfect gas. In addition, the difference in the overall polar profiles is amplified significantly for the reflected shock, and may alter the reflection configuration. Regarding the shock reflection transition criteria, vibration excitation may cause increases of both transition angles, i.e., the detachment criterion and von Neumann criterion, and the increment of the former is much larger than the latter.