Experimental Study On Wave Dissipation And Mechanical Characteristics Of A Single Pontoon-Catenary Floating Breakwater

As the growth of population,development of civilization,science and technology,human’s demand for energy is increasing.As a result,ocean with vast space and resources has gradually become the second largest space for human development except on land.But the exploitation of marine resources is limited by the environment.In order to improve the construction situation and ensure the development of energy,people invented a variety kind of breakwaters.The floating breakwater is composed of the breakwater body and the mooring system,which prevents wave propagation or breaks the wave through the floating body.Under the interaction of the wave,the breakwater body floats up and down and swings back and forth to disturb the water particle movement of the wave,and destroys the flow direction inside the wave,so as to achieve the purpose of reducing wave energy.Moored-pontoon floating breakwater is a kind of structure which is widely used in recent engineering.There are many reports about this type of breakwater at domestic and abroad.However,there are still many problems in the comprehensive research at domestic and abroad.For example,there is little research on the pressure of the buoyancy pontoon,while the pressure is directly related to the safety of the structure.The moored-pontoon floating breakwater is studied in this paper.Based on the experiment,the influence of various cases on the ability of wave elimination,pressure on floating body and mooring line tension are studied.There are analysis of the influence of relative width(B/L),relative draft(S/d),relative wave height(H/d),angle between mooring line and vertical direction(α),mooring line stiffness(K)on the transmission coefficient and stress of floating breakwater in this paper.The results of experiment shows that:(1)The performance on wave dissipation of single pontoon-catenary floating breakwater is mainly affected by relative width(B/L),angle between mooring line and vertical direction(α),mooring line stiffness(K).With the increase of mooring line stiffness,the wave transmission coefficient decreases and the performance on wave dissipation improves.relative draft(S/d)and relative wave height(H/d)have little influence on wave dissipation.(2)With the increase of angle between mooring line and vertical direction,the pressure of floating body tends to decrease firstly and then increase.The minimum pressure present when the angle is 45°.(3)As for mooring line tension,three angles are studied,which are α=30°,45° and 60°.The tension is minimal whenα=45°,and the tension is nearly the same when α=30° and 60°.With the increase of mooring line stiffness,the tension of mooring line is increased.The variation trend of stress on the mooring line backing to incident waves are similar to that of the line facing to incident waves,but the value is generally less.In general,this paper studies the wave dissipation performance and mechanical characteristics of single pontoon-catenary floating breakwater through physical model experiment,and concluded the variation of transmission coefficient,pressure and mooring line tension along with the influencing factors.The conclusion can be used as a reference for the design and engineering application of the single pontoon-catenary floating breakwater.