Separation Shapes Induced by Interactions of Cowl Dual Shock Waves with the Boundary Layer at Various Ramp Geometries of a Hypersonic Inlet

Abstract

This study presents a numerical simulation of hypersonic inlet flows across three geometries: a single ramp, a concave ramp, and a convex shoulder. It aims at understanding the formation and behavior of separation bubbles (SB) over a wide range of Mach numbers. The effects of the angle of attack and the wall temperature on separation bubbles are also analyzed. Due to the complexities associated with the separation bubbles, the simulation is divided into two steps: an initial inviscid simulation that followed by a viscous simulation. The inviscid simulation focuses on the interaction of geometry-induced shock waves, including cowl shock waves and shoulder expansion waves, to clearly characterize the adverse pressure gradients. The viscous simulation then investigates the impact of expansion waves from sharp and convex corners on the complex shock wave boundary layer interactions (CSWBLI) and the interaction of geometry-induced shock waves (GISW) with separation bubble-induced shock waves (SBISW). Computational details such as the inlet model, the numerical methods, the boundary conditions, the grid independence and code validation results are given. The key results highlight the dependency of separation bubble size and shape on geometric, thermal, and flow parameters, providing a deeper insight into the separation bubble behavior and the shock wave interactions in hypersonic flows. The findings contribute to the optimization of inlet design for hypersonic flows.