RR to MR Over a Moving Wedge at A High Supersonic Flow

Changing the wedge's inclination angle in a high-speed flow represents one of the aerodynamic flow controls for supersonic and hypersonic air-breathing vehicles. The transition between the regular reflection (RR) and Mach reflection (MR) phenomenon, which impacts the design of these vehicles, is affected by the wedge's trailing edge motion. This paper presents numerical simulations of the dynamic transition from RR to MR phenomenon at a high supersonic flow of Mach number 4 and compares results with the steady-state transition. The transition phenomenon is studied over a two-dimensional upstream moving wedge, where the trailing edge moves horizontally with a velocity, V(t). The flow field is simulated using an unsteady compressible inviscid flow solver integrated with the Arbitrary Lagrangian-Eulerian (ALE) technique to perform the wedge's movement. The precision of the computational simulations is determined by conducting a mesh-independent study. The dynamic transition from RR to MR is defined with the sonic and detachment criteria. Further, the lag in the shock system is analyzed for different reduced frequencies, kappa = 0.1, 0.5, 1.0, 1.5, 2.0 by measuring the flow characteristic parameters, such as wedge angle, theta(w), the tangent wave angle at the wedge's leading-edge, beta(t), the incident wave angle at the reflection point, beta, and the unsteady Mach stem height, MS. The results show that the detachment criterion occurs at 2.8 degrees after the sonic criterion for kappa = 2. At low-frequency rates of wedge motion, the transition occurs close to the theoretical limit. However, the lag in transition increases and MS decreases as the wedge moves at higher kappa. In addition, the transition from RR to MR occurs above the Dual Solution Domain (DSD) placing it in the MR, Mach Reflection with Subsonic Downstream Flow (MRs), and No reflection domains (Bow shock), depending on the rate of trailing wedge's movement.