Large Eddy Simulation of Supersonic Open-Cavity Flows

A three-dimensional supersonic flow at Mach 1.4 over a rectangular open cavity of length-to-depth ratio L/D = 6, width-to-depth ratio W/D = 2 is studied with large eddy simulation. The numerical results are validated against the experimental data provided in the literature of Dudley and Ukeiley [1] through comparing time-averaged flow patterns and turbulent velocity in the cavity flow. The agreement is reasonable. Furthermore, we analyze the essential dynamics of the cavity flow, e.g. the resonant vortex-acoustic interactions, the dominant flow oscillation. The compressibility effects on the base flow and the pressure and velocity fluctuations are studied subsequently. Additionally, a two-dimensional open-cavity flow at the identical Mach number, Reynolds number and length-to-depth ratio is simulated with direct numerical simulation for reference. The two-dimensional result shows the vorticities are accumulated gradually in the initial stage and then switch the flow pattern eventually. Conversely, the flow in the three-dimensional open cavity could achieve a “stable” turbulence instantly and then maintain the flow pattern.