The flow interaction effects from a transient, pulsed-jet issuing into supersonic, transonic, and subsonic crossflows are investigated computationally for a basic fin-stabilized projectile. This work extends previous studies of the same projectile using steady-state jet simulations. In supersonic crossflows, the resultant control forces due to the reaction jet attain steady state values relatively quickly indicating that the steady state simulation can reasonably represent the unsteady jet response. In transonic and subsonic crossflows there was a significant delay in the resultant control force reaching the steady state value, but the linear and angular impulse amplification factors were still within 6% and 8%, respectively, of those predicted from steady state results. At Mach 1.5 and 0.95, no significant forces or moments were observed acting outside the plane of the jet nozzle. However, at Mach 0.6 a peak side force about 12% of the total JI normal force and a peak side moment about 30% of the total JI pitching moment were observed. The maximum out-of-plane angles were only about 1° for the resultant JI force and 3° for the resultant control force. Steady state simulations using a rolling reference frame method to simulate projectile roll showed that the effects of roll are negligent at roll rates typical of fin-stabilized projectiles in supersonic crossflows. In transonic and subsonic crossflows, roll-induced effects on the resultant control force were found at roll rates that may be encountered in fin-stabilized projectiles.
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