The interaction of a solitary wave with a vertical perforated plate is investigated in this study with particular attention given to the degree of wave reflection, transmission and energy dissipation. In order to understand the physics of the problem, two different numerical models along with sets of experimental data are used. The numerical models differ in capturing the influence of the plate porosity on the flow. In the first, the OpenFOAM package is used to model all details of flow through a small section of perforated plate, providing some confidence in the simulation results due to the high resolution of the simulation. However, such a model is impractical. Hence, in the second approach the interaction was captured by means of a Smoothed Particle Hydrodynamics (SPH) model in which a pressure drop was applied across a narrow (but finite) region of the domain corresponding to the perforated plate. The results of both methods are then compared and verified against experimental data and a proper relationship between the incident wave characteristics, porosity and reflection/transmission coefficients of the perforated plate is presented.
Perforated plates and slotted screens have a wide range of applications in industry and science. For many of these applications, the effect of the perforated plate on the hydrodynamics of the flow, in particular pressure loss, has been measured experimentally and semi-empirical formulations have been developed. In particular, there are number of studies on flow through vertical porous walls (see Suh & Park (1995), Ozahi (2015), Malavasi et al. (2012)) and a comprehensive literature review on the pressure loss through perforated plates in circular and rectangular ducts is given in Weber et al. (2000).
On passing through a screen that is perpendicular to the flow, fluid experiences a mean pressure drop, with the potential for the generation of unsteadiness and turbulence depending on the Reynolds number of the flow through individual holes. On passing through an inclined screen, similar phenomena are encountered but in addition, the fluid is permanently deflected towards a direction that is normal to the screen, indicating the presence of a force that is tangential to the screen surface. One can find theoretical analysis in the studies of flow through gauze screens (see Taylor & Batchelor (1949), Elder (1959)). The fundamental assumptions in the analytical solutions are that the deflection of a streamline when passing through the gauze is small, and that the gauze is uniform and the angle of incidence of the flow on the gauze to be small (see Elder (1959)). These solutions are therefore not applicable for large values of the screen inclination. In addition, each formulation is limited to a special range of Reynolds numbers (see Weber et al. (2000)).