Numerical simulation of flow-induced oscillation and sound generation in a cavity

By solving the two-dimensional unsteady Reynolds averaged Navier-Stokes (URANS) equations, the flow-induced oscillation and sound generation are investigated with a computational aeroacoustics approach. The dispersion-relation-preserving scheme is applied for spatial discretization and the low-dissipation and low-dispersion Runge-Kutta scheme is adopted for time integration. The standard κ-ε turbulence model is employed in the simulation. Appropriate non-reflecting boundary conditions are adopted at the inflow and outflow boundaries. The simulated density field agrees well with Krishnamurty's experimental schlieren photograph. And the first three oscillation modes have been caught and are found to agree very well with the predicted frequencies by Rossiter's empirical formula. Furthermore, it is shown that the thickness of the boundary layer has an important influence on the self-sustained oscillation. Finally, the sound generation mechanism of the oscillation is analyzed and the second sound wave generation phenomenon is detected at the leading edge.