The role of plate-end separation and plate thickness of perforated plates in oscillatory flow

The role of plate-end flow separation, plate thickness and number of openings for the hydrodynamic loads on perforated plates are investigated by a numerical and theoretical study, in infinite fluid conditions with two-dimensional oscillatory flow normal to the plates. An extended Molin model is presented, accounting for the plate thickness; the inertia term in the pressure-drop condition is modified to account for the plate thickness. The effect of plate thickness is shown to be significant for low and medium Keulegan–Carpenter (KC) numbers, although the plates are thin (KC=2πA/D, where A is the flow amplitude and D the plate width). Quantitative measures of the role of plate-end separation are presented by means of comparing hybrid and conventional computational fluid dynamics (CFD) simulations. The two methods converge for low KC− numbers. The hybrid CFD code gives consistent results with the extended Molin model. Fewer openings reduce the damping for low and medium KC− numbers due to the increased inertia effect on the pressure-drop.