Numerical study of three-dimensional developments of premixed flame induced by multiple shock waves

The three-dimensional interactions of a perturbed premixed flame interface with a planar incident shock wave and its reflected shock waves are numerically simulated by solving the compressible, reactive Navier–Stokes equations with the high-resolution scheme and a single-step chemical reaction. The effects of the initial incident shock wave strength (Mach number) and the initial perturbation pattern of interface on the interactions are investigated. The distinct properties of perturbation growth on the flame interface during the interactions are presented. Our results show that perturbation growth is mainly attributed to the flame stretching and propagation. The flame stretching is associated with the larger-scale vortical flow due to Richtmyer–Meshkov instability while the flame propagation is due to the chemical reaction. The mixing properties of unburned/burned gases on both sides of the flame are quantitatively analyzed by using integral and statistical diagnostics. The results show that the large-scale flow due to the vortical motion always plays a dominating role during the reactive interaction process; however, the effect of chemistry becomes more important at the later stage of the interactions, especially for higher Mach number cases. The scalar dissipation due to the molecular diffusion is always small in the present study and can be negligible.