PREDICTION OF ULTRAVIOLET-RADIATION IN NONEQUILIBRIUM HYPERSONIC BOW-SHOCK WAVES

Ultraviolet emissions radiated by nitric oxide and atomic oxygen are c omputed for hypersonic nonequilibrium flow conditions corresponding to the Bow-Shock Ultra-Violet-2 flight experiment, The flowfield is anal yzed using the direct simulation Monte Carlo method, Radiation is then estimated using a nonequilibrium radiation code, New results are pres ented that incorporate a number of recent physical and numerical model s, Good agreement is obtained between flight data and predictions over a range of altitudes for both nitric-oxide and atomic-oxygen emission s, Sensitivity to a number of modelling assumptions of the emissions p redicted at altitudes above 70 km is considered, It is found that the emission is very sensitive to the translational energy accommodation c oefficient, It is also extremely sensitive to the freestream chemical composition assumed. By contrast, the high-altitude emission is insens itive to dissociation and exchange reaction models.