Experiments and Computations on Aerothermodynamics of Blunt-body Hypersonic Flight at Mach 16

摘要

Experiments were performed with Southwest Research Institute's (SwRI) two-stage light gas gun and flight range. The flight of blunt 3.87-cm-diameter blunt bodies at hypersonic speeds was examined before they arrived at their targets. Specifically, projectile speeds of 5.5 km/s were studied in a reduced atmosphere, equivalent to Mach 16. Atmospheres ranged from 30-40 torr and were at ambient temperatures. These pressures correspond to altitudes of 20.4 to 22.2 km (67,000 to 73,000 ft). Angle of attack was up to 12°. The flight was imaged with high speed cameras which allowed an examination of the shock wave, ablation products motion around the projectile, luminosity of the material in the flow, and the behind-body turbulence. The images reveal details of the projectile bow shock and wake structure. CFD computations of the experiments were performed and comparisons of the shock wave structure and localized gas ionization are compared. In addition to the flow structure, the computations were used to examine the aerodynamic characteristics of the projectile, wake profile, surface forces, and local gas temperatures. These simulations provide additional insight into the flight characteristics and environment of the projectile. There is an attempt to confirm the flow constituents based on color and luminosity.