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Free energy variations with contact angle.

To reduce aerodynamic heat and drag, and thus improve the speed of hypersonic vehicles, opposing jet technology has become a research focus because of its excellent heat and drag reduction effect. In this paper, Navier–Stokes equations, the shear stress transport turbulent models, the Gupta chemical kinetics model, and the five-species air model are considered; and a numerical simulation program of hypersonic aerodynamic heat and drag with an opposing jet is developed and verified by existing experimental data. On this basis, the flight conditions of [Formula: see text], 14, and 15 at a 30 km flight altitude are simulated numerically; and the complex flowfield structure of the leading edge of a blunt body with or without the opposing jet is analyzed. It is found that the jet can push away the shock wave, playing a good role in reducing heat and drag. The influence of the pressure ratio, Mach number, and jet temperature on reducing heat and drag is investigated. The results indicate that, under the same conditions, increasing the pressure ratio, increasing the jet Mach number, and decreasing the inlet Mach number will be more helpful for reducing heat and drag; whereas increasing the jet temperature is not conducive to heat reduction and has little impact on aerodynamic drag.

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