Detailed simulation of nitrogen dissociation in shock waves

One of the most important and poorly understood processes in hypersonic flows is the coupling between a molecule’s vibrational state and its dissociation rate. The details of this process affect a vehicle’s aerodynamics and thermal protection requirements. It also has a direct effect on the level of ionization in the flow field. In this paper, we examine the vibrational relaxation and dissociation process near a high Mach number shock wave. The forced-harmonic oscillator and Schwartz-Slawsky-Herzfeld vibrational relaxation models with resonant vibration-vibration exchange are used to simulate the vibrational exchange mechanisms. A classical impulse dissociation model is used to simulate the N₂-N₂ and N₂-N dissociation processes.