Design of an inward turning inlet for low Mach number starting based on side wall splitting and translation

Addressing the challenges of low Mach number startability and vortex suppression in inward turning inlets for hypersonic vehicles, this study proposes a synergistic “geometry-shock-boundary layer” control design method. A coordinated flow-control strategy based on side wall splitting and lateral translation significantly reduces the effective internal contraction ratio of the inlet and optimizes the vortex structure. Numerical simulations and flow characteristic analyses demonstrate the superior performance of the innovatively designed inlet over a wide Mach number range. Compared with conventional inward turning inlets, the proposed configuration reduces the self-starting Mach number from 5.4 to 3.2 and the starting Mach number from 3.6 to 3.0, while markedly improving compression efficiency and outflow uniformity. The numerical results presented above fully validate the effectiveness of the proposed synergistic control method, and offer a novel approach for the wide Mach number adaptive design of fixed-geometry inward turning inlets, with significant engineering application value.