Detailed simulation of nitrogen dissociation in stagnation regions

Vibrational relaxation rates from Schwartz-Slawsky- Herzfeld theory and the forced-harmonic oscillator model are used to study the flow of nitrogen in the stagnation region of a blunt body. The mass conservation equations are coupled to the momentum and total energy equations, and solved using an implicit finite-volume computational fluid dynamics method. The effects of single- and multiple-quantum vibration translation transitions and vibration-vibration transitions are studied. Also, the effect of the mass diffusion of the evicted oscillators across the shock layer is investigated. It is found that highly non-Boltzmann vibrational distributions are present in the flow field. Also, the forced-harmonic oscillator model predicts dissociation from the low vibrational levels only.