Hydrodynamic performance of a dual cylindrical caisson breakwater with dual porous ring plates fixed inside

The interaction of a linear wave with a dual cylindrical caisson breakwater with dual porous ring plates fixed inside is investigated using the matched eigenfunction expansion method. Both the inner impermeable cylinders and the outer porous cylinders are rigidly fixed to the flat seabed. The dual porous ring plates are fixed between the inner and outer cylinders, below the still water level. All porous surfaces are assumed to be thin, which allows the use of Darcy’s law. By matching the boundary conditions between different regions, a set of linear equations with unknown coefficients is obtained and solved to get the velocity potential. After verifying the computational results of this paper with published literature, the effects of the structural parameters and wave incident angle on the hydrodynamic performance of a tandem 5-caisson breakwater are investigated. The results show that it is meaningful to conduct wave diffraction studies on the caisson array as a whole, influenced by the inter-cylinder interactions.