Performance evaluation of submerged dual buoy/porous-membrane breakwaters: Fid-Bau Portal

Performance evaluation of submerged dual buoy/porous-membrane breakwaters

Kee, Sung Tai

This paper outlines the numerical and experimental investigation of wave interactions with fully—submerged and floating dual buoy/vertical porous-membrane breakwaters. A multi-domain boundary element program was developed, based on a discrete porous-membrane dynamic model and simple source-distribution over the entire fluid boundaries. Since the boundary condition on the porous-membrane is not known in advance, the membrane motion and velocity potentials are solved, simultaneously. The accuracy and convergence of the developed program were checked using the energy-conservation formula. The numerical results were further validated through the comparisons with experiments for the optimized model, suitable to the 2-D wave tank. Using the developed program, the design parameters of the optimized experimental model were evaluated by checking the performance of the submerged dual buoy/porous-membrane breakwaters for the varying design parameters: the size of the buoy, the membrane tension and spacing, the submergence depth, the gaps between seafloor and end of membranes, and the mooring type and stiffness. The numerical results were found to be in fairly good agreement with the experimental results. From our experimental and numerical examples, it can be concluded that the submerged dual buoy/porous-membrane, if properly designed, can function as a very effective breakwater.