3D flow structure around a piezoelectrically oscillating flat plate

Flow simulations have been conducted to analyze the three-dimensional flow around a vibrating flat plate confined with two endwalls. A smoothing technique for hexahedral grids was implemented without a local re-meshing technique in order to resolve complex flow in a small gap between the fan side and the endwall. Three-dimensional numerical results showed a good agreement with experimentally measured data and the two-dimensional results in a previous work. In time-averaged flow analysis, the flow generated by the plate tends to move toward the center of it so that the velocity magnitude at the center is much larger than other heights near the endwall. It was found that three-dimensional velocity distribution is closely related to the interaction of two kinds of vortices from the fan tip and the fan side. The tip vortex and the side vortex interfere each other near the plate corner and weaken their intensity. In instantaneous flow analysis, an isosurface of λ2 is adopted to analyze a complex vortical structure around the oscillating flat plate. Based on the numerical results, an attempt has been made to understand three-dimensional flow generated by a confined oscillating flat plate.