Wave scattering by dual submerged horizontal porous plates

• Interaction between oblique waves and dual porous plates was investigated.
• Analytic solutions are proved identical with multi-domain BEM solutions.
• Analytical/numerical solutions are compared with the experiments in 2D wave tank.
• Optimal design parameters were found from the systematic parametric study.

The interaction between oblique incident waves and dual submerged horizontal porous plates has been investigated in the context of the two-dimensional linear potential theory including viscous effect through Darcy's law. The matched eigenfunction expansion method(MEFEM) for multiple domains is applied to obtain the analytic solutions. The analytic solutions are verified through comparisons with the independently developed multi-domain BEM(boundary element method) solutions based on simple-sources (second-kind modified Bessel function). The BEM solutions are further used for more general cases including inclined porous plates. Both analytical and BEM solutions are also verified against a series of experiments conducted in a two-dimensional glass-walled wave tank at Jeju National University. In the comparison, the empirical relationship between the plate porosity and porous parameter obtained by Cho and Kim (2008) was successfully applied. The dependence of the reflected and transmitted coefficients on the design parameters, such as porosity, submergence depth, plate width, gap distance, wave heading, inclined angle of the plate, and wave length, is systematically analyzed. It is found that the performance of the proposed dual submerged horizontal porous plates can be significantly enhanced by selecting optimal design parameters for the given wave condition. The upper porous plate plays a major role in wave blocking performance but the presence of lower porous plate may be important when tidal variation is large.