Numerical Investigation of Jet Interaction in aSupersonic Freestream

Abstract

The objective of this investigation is to numerically evaluate effects of a reaction control (divert) jet on the aerodynamic performance of a generic interceptor missile operating at supersonic flight conditions. These effects include transient operation, external chemical reactions, burning, and geometric scale (full scale versus subscale). Three-dimensional computations of the highly turbulent flow field produced by a pulsed, supersonic, lateral-jet control thruster interacting with the supersonic freestream and missile boundary layer of a generic interceptor missile are evaluated. A generic missile interceptor configuration consisting of a long, slender body containing fixed dorsal and tail fins is simulated in this study. Parametric computational fluid dynamic solutions are obtained at altitude conditions corresponding to 19.7 km for the following scenarios: 1) steady-state conditions with the lateral control jet turned off; 2) steady-state conditions with the lateral control jet turned on; 3) steady-state conditions with the lateral control jet turned off with 1/10 subscale; 4) steadystate conditions with the lateral control jet turned on with 1/10 subscale; 5) transient jet startup conditions; 6) transient jet shutdown conditions; 7) steady-state, finite-rate chemistry; and 8) steady-state, frozen calculations with the chemical reactions “turned off.” A thermally and calorically perfect gas with a specific heat ratio equal to 1.4 was assumed for both the transient and geometric scale calculations. Vehicle forces and moments are assessed from each solution by integrating the surface pressures and viscous shear stresses computed on the missile surfaces. These results are used to determine the influence of the jet interaction effects on the transient, external burning, and geometric scale aerodynamic performance of the missile. The analysis predicts strong transient influences, small external burning influences, and very small full-scale vs 1/10-subscale effects for the integrated normal force and pitching moment.