Progress in multi-wave structure and stability of oblique detonations

Oblique detonation is an important direction in gaseous detonation physics and has great potential in the application of new-concept aeronautic and astronautic propulsion. As the fast combustion induced by shock, the oblique detonation wave could be simplified into a discontinuity with energy input. However, in oblique detonation flow, there concern several complicated fluid phenomena, such as shock wave and turbulence, which are coupled with the heat release and result in complicated flow and combustion mechanisms. A theoretical investigation is hard to be performed due to the characteristics of multi-scale and nonlinearity. Meanwhile, experimental investigation encounters the difficulties from measuring the flow fields of high temperature, high pressure, and high velocity. In the last two decades, the main progress of oblique detonation is achieved by numerical investigation through comprehensive simulation and analysis. First of all, the multi-wave structure of the initiation region and surface stability are introduced in the ideal inflow conditions. Then, derived from the application in engines, the effects of inflow inhomogeneity and interaction with expansion waves are studied and analyzed. Finally, some suggestions on future work are proposed and discussed.