Interaction of waves and a porous cylinder with an inner horizontal porous plate

Theoretical work of a partly porous circular cylinder is studied in the present work. The cylinder possesses a porous sidewall and an impermeable bottom. In addition, a porous plate is fixed horizontally inside the cylinder, either beneath or coincident with the water’s surface. The inner plate is to work as an obstruction to make wave dissipation more effectively. To simplify the problem, the Darcy’s fine-pore model is applied to the boundary condition on the porous body surface. Special treatment is required for the boundary condition on the inner porous plate when it is situated at the still water surface. A new boundary condition is derived at that part of the boundary based on the linear wave theory and Darcy’s law. To validate the theoretical work and computed results, a series of model tests are carried out in a wave basin. It is found that the computed results with the present method are generally in good consistence with the experimental data. The discussion on the effects of porosity and the inner plate is presented as well.