Irregular configurations of shock wave impingement on reactive mixing layers.*

This study investigates the impact of an oblique shock wave at a specific angle on a hydrogen-air mixing layer formed by two supersonic streams with different Mach numbers. The interaction between the shock wave and the reactive mixing layer can result in the formation of regular or irregular structures. The regular configurations, which aim to achieve equilibrium following the incident and transmitted shock waves, can be formed through a reflected wave or a Prandtl-Meyer expansion. These regular configurations occur within critical limits, and exceeding these limits prevents the flow from reaching equilibrium downstream of the oblique shock. In such cases, the flow exhibits irregular configurations characterized by new structures, including slip lines, triple points, curved shocks, or subsonic regions.

Prior research has primarily focused on studying these phenomena using a non-reactive shear [1] or mixing layers in supersonic coflows. However, this work aims to explore more realistic configurations by considering a multi-species fluid field. To achieve this, direct numerical simulations (DNS) are conducted using CREAMS, a high-fidelity solver that employs a seventh-order hybrid weighted essentially non-oscillatory (WENO) scheme for spatial discretization and a 3rd-order Runge-Kutta scheme for time integration. This study aims to provide valuable insights into the unstable behavior commonly observed in scramjet combustors upon change of operation regimes.