A numerical investigation of flow dynamics inside wall cavity and strut cavity placed in supersonic airflows

A study on flow dynamics in strut cavity and wall cavity in different freestream Mach numbers using numerical simulations has been conducted. A strut cavity is the space between two struts longitudinally aligned next to each other, and a wall cavity is the cavity in the wall. Our earlier results showed that both cavities exhibited oscillations for low values of supersonic Mach numbers, while oscillations decreased for high values. However, the strut cavity responded better to the change in Mach number than the wall cavity. The present work explores wave propagation and wave interactions inside the cavities in different Mach number flows. It is shown that the flow velocity inside a cavity affects wave propagation. Secondary recirculation inside the cavities has been discussed. The work also revisits the process of wave generation inside the cavities. Furthermore, an insight into the vortex propagation along the cavity length has also been provided. The results suggest that the vortex velocity may not remain uniform throughout the cavity length and may depend on the flow Mach number. Finally, the mass exchange between the cavity and the freestream is described and compared for different cavities. Flow particles are tracked in the shear layer and inside the cavity to suggest the locations of mass exchange.