On three-dimensionality and control of incompressible cavity flow

The incompressible large eddy simulation technique, coupled with the Lighthill-Curle acoustic analogy, is used to investigate the oscillation mechanism and sound source of a two-dimensional cavity with a length-to-depth ratio of L∕D=4 and Reynolds number of ReD=5000. It is demonstrated that the development of the three-dimensional flow field, initiated by the introduction of a random inflow disturbance, is eventually accompanied by transition from the wake to the shear layer oscillation mode, regardless of the amplitude and shape of the inflow disturbance. Once the transition to the shear layer mode is accomplished, the amplitude and frequency of oscillations are not very sensitive to the particular shape of the inflow disturbance. The effectiveness of controlling the flow oscillations by applying simultaneous steady injection and suction through the front and rear cavity walls, respectively, is demonstrated. The results show that, for injection levels exceeding a certain threshold value, the oscillations...