Ballistic Range Experiment and Numerical Simulation of Shock Stand-Off Distances Over Spheres in CO 2

To provide experimental data for validation of numerical simulations, measurement of shock stand-off distances over spheres in CO2 has been made in the hypervelocity ballistic range of Hypervelocity Aerodynamics Institute, China Aerodynamic Research and Development Center. The models were spheres with a diameter of 10 mm. The flight speeds were between 2.122 km/s and 4.220 km/s, with ambient pressures between 2.42 kPa and 12.3 kPa. The shock stand-off distance was measured using shadowgraph. Results revealed that high-temperature gas effect is more obvious in CO2 than in air, while two-temperature nonequilibrium model can basically reproduce the shock stand-off distances over spheres under present test conditions. The flow over spheres of present test is speculated to be mainly nonequilibrium. The accuracy and capability of two-temperature nonequilibrium model in CO2 may differ with different flow speeds and pressures, which need to be further investigated.