Study On Wave Dissipation Performance Of OWC-perforated Double Body Floating Breakwater

With the progress of science and technology and the improvement of the quality of human life,people have made more and more in-depth exploration of the ocean.The floating breakwater has attracted more and more attention because of its advantages of convenient installation,convenient construction,simple maintenance,and water quality exchange.On the one hand,compared with the single body floating breakwater,the double body floating breakwater has better wave dissipation performance.On the other hand,under the background of promoting global carbon neutrality,wave energy is one of clean energy.Therefore,the research and development of floating breakwater with better wave dissipation performance and taking into account wave energy power generation and other functions has become a research hotspot in recent years.Based on the boundary element method,the numerical model of the floating breakwater is established by using ANSYS Aqwa.The results of the amplitude response operator of the floating breakwater,the transmission coefficients of several floating tanks with different structures,and the wave surface elevation of the breakwater are compared with the literature results,so as to verify the accuracy of the numerical model.In order to understand its wave dissipation performance,this paper simulates the transmission coefficient of the twin body floating breakwater under the action of regular and irregular waves.By changing the working condition parameters and wave elements of the structure,the effects of water depth,wave period,wave incidence angle,incident wave height,twin body spacing,anchoring mode,and the opening width of the OWC device on the transmission coefficient are studied.The results show that under the wave conditions studied in this paper,the double body floating breakwater has better wave dissipation performance than the ordinary double floating breakwater;Under the action of regular waves,the wider the distance between two bodies and the width of OWC opening,the better the wave dissipation effect;The wave dissipating performance of the floating breakwater without cable dragging is slightly better than that of the floating breakwater with cable dragging;The wave attenuation effect of normal incidence is better than that of oblique incidence.Under the action of irregular waves,the rules of the distance between two bodies,the width of OWC opening and the incident angle of waves are the same as those of regular waves;The significant wave height has little influence on the wave dissipation effect,but with the increase of the significant wave height,the influence also increases;The water depth has a great influence on the transmission coefficient.In order to understand the stability characteristics,the motion amplitude response operator(RAO)of the OWC perforated twin body floating breakwater is analyzed in this paper,and the laws affecting the stability of the breakwater are obtained.The effects of different incident wave angles,twin body spacing,OWC opening width,draft and anchor chain dragging length are emphatically studied.The results show that under the wave conditions studied in this paper,the motion amplitude response operator of OWC perforated double body floating breakwater is larger than that of similar breakwater in the rolling direction;The distance between two bodies has no obvious effect on the stability of the structure;In pitch direction,the motion amplitude decreases with the increase of incident wave angle;With the increase of the width of the OWC opening,the motion amplitude response operator also increases,especially in the pitch direction;Increasing the draft of the floating breakwater or decreasing the length of the anchor chain dragging the ground will increase the amplitude response operator of the floating breakwater in the heave and roll directions,decrease the amplitude response operator of the floating breakwater in the pitch direction,and increase the natural period of the floating breakwater.This study can provide a theoretical basis for the design and application of floating breakwaters,and has great practical significance for the research and development of integrated devices of floating breakwaters and wave energy power generation.