PREDICTION OF VIBRATIONAL-RELAXATION IN HYPERSONIC EXPANDING FLOWS .2. RESULTS

This article examines the range of applicability and performance of th e Landau-Teller vibrational relaxation model and a simplified anharmon ic model in expanding flows. The simplified relaxation model allows bo th non-Boltzmann population distributions and includes anharmonic tran sition rates and energy transfer. A coupled set of vibrational transit ion rate equations and quasi-one-dimensional fluid dynamic equations i s solved. The calculations are compared with experimental results obta ined in nozzles. The predictions of the detailed master equation solve r are in excellent agreement with experimental results. Although the s implified anharmonic model requires significantly less computational t ime than the master equation solver, it gives good agreement with the detailed solver and with experimental test results.