Analysis of [pi]-type floating breakwater in oblique waves

The present study investigates the diffraction problem of waves interacting with a long rectangular breakwater with two side plates, for brevity it will be referred to as pi-type. The effect of the addition of two side-boards on the performance of a rectangular breakwater is the main aim of this study. The structure is assumed to be placed in water of uniform constant depth, and an eigenfunction expansion method was used in the solution. The fluid is assumed inviscid, and the flow irrotational, so that a velocity potential may be used to describe the flow. The exciting forces, added masses, damping coefficients, responses of the structure, and the transmission coefficient were all calculated for different cases and their results were analyzed. Different waves approaching the breakwater from any direction are considered. Comparisons between the present approach and different numerical solutions published previously were used to verify the developed numerical model. Other comparisons between the traditional rectangular breakwater and the proposed pi-type breakwater are also performed. The present solution proved to be a fast accurate method as compared to other methods. The present study showed that maximum wave forces and heave response occur for the normal wave incidence, but the surge and pitch responses are not maximum for normal waves and different directions then need to be considered. The proposed breakwater experiences lower exciting forces when compared to a rectangular one having the same under-tip clearance, thus savings of materials and cost are achieved by using this type, provided its good performance with respect to wave transmission is assumed. The numerical results showed good agreement with the measured transmission coefficient for both the fixed structure and freely floating structure cases.Applied Science, Faculty ofCivil Engineering, Department ofGraduat