Numerical Investigation of Supersonic Jet Interaction for Finned Bodies

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Abstract : A detailed numerical investigation of the interaction between a lateral jet and the external flow has been performed for a variety of missile body geometries. These include non-finned axisymmetrical bodies and finned bodies with either strakes or aft-mounted tail fins. The computations were performed at Mach numbers 2, 4.5, and 8. To obtain the numerical results, both Reynolds- averaged Navier-Stokes and Euler techniques were applied. The computational results were compared with results from a previously published wind tunnel study that consisted primarily of global force and moment measurements. The results show significant interactions of the jet-induced flow field with the fin surfaces, which produce additional effects compared with the body alone. In agreement with the wind tunnel study, in some cases the presence of lifting surfaces resulted in force and/or moment amplification of the jet interaction with the missile surfaces. The results indicate deamplification of the jet force at Mach 2 for all three bodies. Amplification of the jet force was also observed for high Mach numbers, particularly for the body with strakes. For the results examined here, there were only minor differences in the global force and moment predictions when viscous or inviscid techniques were used. The dependence of the interaction parameters on angle of attack and jet pressure was well predicted by both methods. The numerical techniques showed good agreement with the experiments at supersonic Mach numbers but only fair agreement for the hypersonic, Mach 8 case.