Factors Affecting Reaction Jet Interaction Effects on Projectiles

Abstract

The flow interaction effects from a jet issuing into a supersonic crossflow were investigated computationally for the case of a flat plate and a generic fin-stabilized projectile. For both configurations, simulations were performed at several Mach numbers and jet total to freestream static pressure ratios (PR). Several additional parameters were investigated using the flat plate configuration, e.g., nozzle exit to throat area ratio, jet total temperature, and freestream altitude. In the flat plate case, the jet force was generally amplified, with a strong dependence on PR and the freestream Mach number. In the projectile configuration, the jet force was generally attenuated, unless the jet was located very close to the tail fins. In the latter case, this results from a combination of little or no projectile surface area for the detrimental jet interaction effects to act on and the high pressures developed on the fin surfaces. The choice of turbulence model was found to be an important parameter, making the availability of experimental validation data is important.