Numerical investigation of flow-induced oscillations and noise from a rectangular cavity.

Direct numerical simulation is used to investigate flow-induced oscillations and noise for a low-Reynolds-number subsonic flow over a rectangular cavity with a constant configuration L/D=2. The results indicate that oscillations are dominated by Rossiter II mode in the range of present computational parameters. A low frequency component appears as the decreasing of the thickness of inflow boundary layer, which is directly caused by pattern switching of vortex-edge impingement. The inherent reason is unstable interaction between the recirculation zone and the shear layer. The proper-orthogonal-decomposition (POD) method is employed to analyze the influence of different oscillation pattern on the corresponding vortex structures of the intrinsic mode and its relation with vortex-edge interaction. Moreover, the process of noise generation and propagation is computed and analyzed, and the results are agreed well with available experiments and analytical model. [ABSTRACT FROM AUTHOR]