Mechanism of Mach stem-induced initiation in non-uniform supersonic inflow with transverse injection

This study identifies a Mach-stem-triggered detonation under supersonic inflow with realistic injection mixing. High-resolution simulations demonstrate that boundary-layer flame acceleration generates Mach stems, whose interactions with reflected shocks create localized high-pressure and high-temperature regions exceeding the critical detonation threshold. This process relies on localized thermodynamic intensification, requires no artificial obstacles, and can be robustly initiated by microsecond-scale ignition jets, providing a novel pathway for achieving detonation under low-energy ignition conditions.