PREDICTION OF VIBRATIONAL-RELAXATION IN HYPERSONIC EXPANDING FLOWS .1. MODEL DEVELOPMENT

A number of experiments in nozzles have indicated that the Landau-Tell er vibrational relaxation model fails to accurately predict the relaxa tion process in expanding flows. In the present study vibrational tran sition rate equations are solved and the detailed calculations are use d to develop a simplified relaxation model. The present simplified rel axation model allows both non-Boltzmann population distributions in vi brationally heating and cooling flows. This simplified model also incl udes the effect of anharmonicity on vibrational transition rates and e nergy transfer.