Experiment and numerical simulation of axial incident shock wave reflection and focusing process

To study the effects of the shock wave focusing on the second stage process of the twostage pulse detonation engine by the cavity entrance widths, an experimental system was designed to research axially incident shock focusing on the different cavity entrance widths. And experiment and numerical simulation were carried out to investigate the process and the effects of the reflected shock wave focusing. The schlieren system was used to photograph the structure of the cavity flow field, and the dynamic pressure on the vertex was measured. Strong stabilitypreserving (SSP) RungeKutta method, and weighed essential nonoscillation (WENO) scheme and block structured dynamically adaptive mesh refinement (SAMR) algorithm were adopted to simulate the shock wave reflection, diffraction and focusing process. Good agreement between experiments and numerical results was observed. By analyzing and comparing the shock wave reflection and focusing process under the conditions of the same Mach shock wave through different entrance cavity widths, the enhancement of the reflection and focusing and the increase of the vertex pressure with a smaller width were found. Meanwhile, the jet enhancement was induced by the shock wave focusing.