Regular to irregular shock reflection transitions for shock-shock interactions and shock-surface scenarios

Mach stems are generated under certain types of conditions and this can happen when several shock fronts interact, or when a shock front interacts with a surface. A Mach stem generates a localized region characterized by higher pressure, temperature and density when compared to the incident shock front. Understanding when a Mach stem forms and how it propagates is of interest when it comes to, for example, shock-shock interaction events or shock interactions with solid surfaces. Here, Mach stem formation was studied in a laboratory setting using an exploding wire system, which allowed for rapid experiment iteration and exceptional cost effectiveness compared to large-scale experiments or computational modeling. The experimental system is modular and can be easily modified to analyze shock-shock or shock-surface interactions, both of which can be set up as either a 2D or a 3D case. Data was collected via pressure sensors and ultra-high-speed schlieren imaging, and then analyzed to determine the point of Mach stem initiation and Mach stem propagation properties.