Iain D. Boyd and Wyatt Phillips
Sibley School of Mechanical and Aerospace Engineering
Cornell University, Ithaca, NY
Deborah A. Levin
Institute for Defense Analyses, Alexandria, VA 22311
Ultra-violet emissions radiated by nitric oxide and atomic oxygen are
computed for hypersonic nonequilibrium flow conditions corresponding to
the Bow-Shock Ultra-Violet-2 flight experiment. The flow field is
analyzed using the direct simulation Monte Carlo method. Radiation is
then estimated using a nonequilibrium radiation code. New results are
presented that incorporate a number of recent physical and numerical
models. Good agreement is obtained between flight data and predictions
over a range of altitudes for both nitric oxide and atomic oxygen
emissions. Sensitivity to a number of modeling assumptions of the nitric
oxide emission predicted at the highest altitude condition is considered.
It is found that the emission is very sensitive to the translational
energy accommodation coefficient. It is also extremely sensitive to the
free stream chemical composition assumed. By contrast, the high altitude
emission is insensitive to dissociation and exchange reaction models.