Performance of Submerged Floating Breakwater Supported by Perforated Plates under Wave Action and Its Dynamics: Fid-Bau Portal

Performance of Submerged Floating Breakwater Supported by Perforated Plates under Wave Action and Its Dynamics

Mizutani, Norimi / Rahman, Md. Ataur

With the increasing demand of multi-purpose use of coastal and offshore zone, the floating breakwaters are being constructed as a good and cost effective substitute for the conventional type of breakwaters. In the case of deep water areas, floating breakwaters are easier to build than gravity type breakwaters made of concrete caissons. It has gained significance in recent years because of its basic advantages, such as flexibility, easy mobilization, installation and retrieval. A rectangular-shaped floating breakwater is proposed here to reduce the transmitted wave height and to control the incoming wave energy. An experimental study is carried out in a two-dimensional wave tank to evaluate the performance of the proposed breakwater. Three different types of mooring systems, with three different inclination anchorage of each system, are adopted in this experimental study. Two of them are perforated wooden plates. The other one is chain mooring system that was adopted for comparison. The experiments are carried out for 3 different water depths, 3 different wave steepnesses and 10 different wave periods, that result a total 810 cases of experimental runs. The reflected and transmitted wave heights, water particle velocities and the displacements of the floating body (sway, heave and roll) are measured during the experiment. It is observed that a good amount of the incoming wave energy is dissipated by the breakwater in most of the cases. Comparisons among the performances of the floating body with three different types mooring systems with various inclination of the mooring anchorage are done. All the results and analyses are presented in this paper. The very good performance of this type breakwater to absorb the incoming wave energy, its easy installation and mobilization characteristics and less construction and maintenance cost demand and justify its use in the real field of coastal engineering.