Hydrodynamic Characteristics of Vertical Cellular Breakwater

Abstract

Permeable and slender coastal protection systems are gaining ground in the field because they are relatively economical and easy to construct compared to traditional-type breakwaters. In this study, a breakwater consisting of prefabricated rectangular cells with two vertical permeable walls supported by two rows of vertical circular piles was proposed. The vertical wall consisted of a perforated upper part and a lower part with horizontal slots. The number of cells varied depending upon water depth. The wave transmission, reflection, and energy dissipation characteristics of the breakwater under regular waves for a normal angle of incidence were studied experimentally and analytically. The hydrodynamic characteristics of the proposed breakwater were investigated for different wave conditions and different structural parameters. Studies were carried out for different values of relative upper-part submergence from a still water level (SWL) and also by varying the porosity of the upper portion and the relative spacing between the walls. An eigenfunction expansion method was used to develop the analytical model to study the hydrodynamic performance of the breakwater. The results reveal that a reasonable agreement was obtained between the experimental and analytical models; however, in some cases, the analytical model slightly underestimated the hydrodynamic characteristics by no more than 10%.