Shock Interaction with a Large-Amplitude Sinusoidal Perturbation on a Fast-Slow(F/S) Gaseous Interface*

Shock Wave refraction on a perturbed density interface causes dilatation of interface perturbations, and deposition of baroclinic vorticity. On an F/S interface, a large interface perturbation could lead to transition from a regular refraction (i.e., the incident, reflected and transmitted shock has triple point on interface) to an irregular Mach reflection refraction pattern. Correct modelling of these early time interactions is of fundamental importance to supersonic mixing problems such as scramjet injectors and ICF fuel capsule designs. The objective of our study is to develop a model for interface morphology and circulation deposition during the whole interaction phase. As a model for curved interface, we consider a series of slanted planar interfaces and employ shock wave refraction theory and shock polar method to predict transition between different regimes and to solve the flow field of refraction patterns. We also study the structure and hysteresis of the Mach Reflection Refraction (MRR) system on a curved interface in detail. Our model, grounded in analytical techniques in gas dynamics, is then verified by comparison to high-order-accurate numerical simulations