LARGE EDDY SIMULATION OF THE COMPRESSIBLE FLOW OVER A CAVITY WITH HIGH ASPECT RATIO

다국어 초록 (Multilingual Abstract)

Large eddy simulation is used to investigate the compressible flow over a cavity with high aspect ratio. The sub-grid scale stresses are modeled using the dynamic model The compressible Navier-Stokes equations are solved with the sixth order accurate compact finite difference scheme in the space and the 4th order Runge- Kutta scheme in the time. The buffer zone techniques are used for non-reflecting boundary conditions. The results show the shear layer oscillation over the cavity. The votical disturbances, the roll-up of vorticity, and impingement and scattering of vorticity at the downstream cavity edge can be seen in the shear layer. Several peaks for the resonant frequencies are found in the spectra of the vertical velocity at the center-line, The most energetic peak near the downstream edge is different from that at the center part of the cavity. The pressure has its minimum value in the vortex core inside the cavity, and becomes very high at the downstream face of the cavity. The variation of the model coefficient predicted by the dynamic model is quite large between 0 and 0.3. The model coefficient increases in the stream-wise evolution of the shear layer and sharply decreases near the wall due to the wall effect.