Real-Gas Effects for Shock/Shock Interaction in Earth and Mars Atmospheres

Abstract

Shock/shock interactions of types IV, V, and VI are simulated for Earth and Mars conditions using perfect-gas, real-gas chemical nonequilibrium (real-gas CN), and real-gas thermochemical nonequilibrium (real-gas TCN) solvers for double-wedge configurations. In type IV interactions, the real-gas flow has normal shock closer to the second wedge as compared to the perfect-gas assumption. Similarly, for type V Mach reflection interaction, the Mach disk is noticed to shift downstream for the planet Earth conditions; whereas for the Martian case, transition to the type V regular reflection (RR) is observed. No noticeable change is evident in the type VI shock pattern for either atmospheric case. Increments in the freestream stagnation enthalpy, in both the planetary conditions, transforms the type IV interaction to type V (RR) and type V to a type VI when real-gas CN is assumed. Furthermore, the type VI interaction portrays a thinner shock layer. Although the shock structure is independent of stagnation enthalpy for a perfect-gas, simulations for high-enthalpy airflows using the real-gas TCN solver reveal resistance to shock transformations, unlike what is seen using the real-gas CN solver. But, the shock pattern is analogous for Martian conditions at simulated enthalpies for both of the real-gas models.