Multi-temperature fluid-dynamic model equations from kinetic theory in a reactive gas: The steady shock problem

Starting from a simple kinetic model for a chemical reaction, multi-temperature reactive Euler equations are derived for physical regimes in which evolution is driven by elastic collisions within the same species and mechanical relaxation is faster than the thermal one. The achieved hydrodynamic equations, where all inhomogeneous exchange rates take analytical closed form for simple collision models, are then used for the analysis of the steady shock problem. Results indicate that smooth shock profiles occurring for slightly supersonic flows bifurcate to weak solutions (jump discontinuity followed by a smooth tail) for increasing Mach number.