On the evolutions of triple point structure in wedge-stabilized oblique detonations

Abstract

The oblique detonation induced by a two-dimensional semi-infinite wedge is simulated numerically with the Navier–Stokes equations and a detailed H2/air reaction model based on the open-source program-Adaptive Mesh Refinement in Object-oriented C++. A spatially seventh-order-accurate weighted essentially non-oscillatory scheme is adopted for the convective flux discretization. The formation and evolution of the oblique detonation induced by wedges at different angles and inflow conditions are investigated, and a prediction model for the oblique detonation flow field is proposed. The results show that the formation of the oblique detonation flow field can be divided into two processes. The first process is similar to the oblique shock flow field with unreactive inflow. When the inflow passes through the wedge, the oblique shock wave starts to form at the tip, followed by the unstable curved shock surface and triple point. In this process, a thin reaction layer is formed on the wedge front, but the thickness of the reaction layer is almost constant. The second process is similar to the process of deflagration to detonation. As the reaction rate increases, the deflagration front is fixed on the wedge, the reaction layer thickens, and the deflagration front gradually approaches the oblique shock wave. When the deflagration front is coupled with the oblique shock wave, the oblique detonation is formed. Moreover, a theoretical prediction model for the triple point location is proposed. Compared with the numerical simulation results, the theoretical model prediction for the position of the transition point of the oblique shock wave–oblique detonation wave is relatively acceptable.