Numerical Simulation of Refraction of Gaseous Detonation Waves at Temperature Interfaces

The refractive behaviors of shock waves and detonation waves during their propagation and damage processes in gaseous media are studied. A computation program with finite volume method and adaptive mesh refinement method is developed based on the reactive Euler equations coupled with a two-step chemical reaction model. The transmission and refraction processes of shock waves and detonation waves at temperature interfaces are determined through theoretical analysis and numerical simulations. The variations of the transmitted shock wave speed and post-wave state with the amplitude of interface temperature are presented, and the typical shock wave structure is obtained. The refraction phenomenon of detonation waves at the temperature interface is further studied, and then the evolution process of cellular detonation wave is analyzed using numerical schlieren and smoked foil method. The results indicate that a shock wave forms a Mach stem and oblique shock wave at the interface when it refracts into low-temperature gas, and it generates a double triple-point structure and a convex wave front when entering high-temperature gas. The cellular detonation wave forms an inclined wave front at the interface when it refracts into low-temperature gas. In contrast, when entering high-temperature gas, it generates a convex wave front and a degenerated double triple point structure. The propagation of cellular detonation waves exhibits distinct spatio-temporal evolution properties.