Study on aerodynamic loads at the inlet’s cowl lip induced by multiple shock-shock interferences

For hypersonic vehicles powered by air-breathing propulsion, multiple shock-shock interferences (MSSI) tend to induce extreme aerodynamic loads at the inlet’s cowl lip, imposing higher requirements on the design of the vehicle’s thermal protection system. This study provides a detailed theoretical and numerical prediction on the aerodynamic loads for MSSI created by two incident oblique shock waves intersecting with the bow shock wave. Concomitant jet (CJ) and dual jet (DJ) are the two main configurations of MSSI, respectively, corresponding to the case where a slip line or a subsonic region separates the two incident-shock-induced supersonic jets. The theoretical analysis indicates that the peak pressure amplification in the DJ mode is almost twice that of the CJ mode under the same boundary conditions. Inviscid transient numerical simulations are carried out to validate the theoretical findings. The numerical results verify the relative relationship between the magnitude of the surface peak pressures induced by different interference patterns given by the theoretical analysis. It is found that the theoretically predicted surface peak pressure is slightly lower than the numerical calculations. The DJ configuration consisting of two type IV supersonic jets is numerically confirmed in this paper.