Submerged breakwater of a flexible porous membrane with a vertical flexible porous wall over variable bottom topography

An analytical model of oblique wave interaction with a breakwater consisting of a submerged horizontal flexible porous membrane near a vertical porous barrier over variable bottom topography is developed based on linear water wave theory. Using Green's second identity, a mild-slope equation for oblique waves propagating over a submerged porous membrane and a finite variable bottom topography is derived. The analytical solution of the referred problem is obtained by using the eigenfunction expansion method along with the mild-slope equation and Darcy's law is used for wave past horizontal and vertical porous structure. The present results are compared with existing published analytical results and experimental data and observed that they have a good level of agreement. The effect of different design parameters on the wave quantities and wave forces on the porous wall in variable bottom depth is analyzed. It is found that full-wave reflection is drastically reduced and the wave energy is dissipated by the submerged horizontal flexible porous membrane and porous barrier. The analysis of the reflection and dissipation coefficients as well as wave forces on the vertical wall in terms of wave energy dissipation and wave loads by the proposed submerged flexible porous breakwater will be helpful for better understanding in the design of various types of protecting infrastructures for marine operations.