Aerodynamics of Low-Blowing-Ratio Fuselage Injection into a Supersonic Freestream

A parametric characterization of the surface flow structure and associated aerodynamic loading for injection into a Mach 3.0 freestream through jets mounted into the side of missile fuselage (sharp-coned cylinder) was experimentally achieved. The experimental methods included surface oil flow visualization, shadowgraph photography, and pressure-sensitive paint. The range of jet-to-freestream pressure ratios spanned 0.6-19.0, which corresponds to an effective backpressure ratio range of 0.19-6.15. Hence, overexpanded, perfectly expanded, and underexpanded jets were tested. The temperature ratios spanned 1.0-13.6, where helium was used to simulate the highest temperature. The nondimensional momentum parameter ratio (MPR) varied over a range of 0.005-0.09. It was observed that the injection temperature for a given MPR had a small effect on the boundary-layer separation distance. For the range of conditions tested, the interaction force increased linearly with increasing MPR. The amplification factors for the lowest MPR values were found to be higher than expected trends.

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