Ballistic range experimental results of radiating wakes of spheres at Mach 10

The hypersonic flow field can experience significant thermochemical nonequilibrium effects. However, very little ground test data exist for nonequilibrium hypersonic wake flows. Simulating air chemistry in nonequilibrium is highly challenging due to the lack of validation data. To address a lack of validation data, ballistic free flight tests were conducted to examine nonequilibrium chemistry effects in the wake of 25 mm spheres at Mach 10. A laser-based diagnostic system was used to measure naturally produced nitric oxide (NO) concentrations. Measurements were made up to 53 body diameters behind the sphere. NO concentrations in the wake peaked between 4.1<i>%</i>±0.8<i>%</i> and 6.8<i>%</i>±1.3<i>%</i>.