Experimental Investigation On The Hydrodynamic Characteristics Of Rubber Pontoon Breakwater

Based on a practical engineering,a rubber pontoon breakwater is presented.Hydrodynamic characteristics of this kind of breakwater has been investigated by physical model tests.Under the action of irregular waves,wave attenuation properties and mooring force of the breakwater are influenced by relative underwater depth of the floating breakwater,mooring methods and number of the mooring lines.Experiment is also carried out for bimodal spectrum waves and the results are compared with the case of irregular waves.The results show that,relative underwater depth of the floating breakwater has a big influence on hydrodynamic characteristics of the floating breakwater.In the range of this paper,increasing the relative underwater depth is good for wave attenuation properties and mooring force of the breakwater.Mooring methods and number of the mooring lines have important effects on mooring force.Compared with the Cross-shaped arrangement,parallel arrangement of the mooring lines is safer for the floating breakwater.Increasing the number of mooring lines results in the reduction of seaward mooring force.For bimodal spectrum waves,the hydrodynamic characteristics of the floating breakwater show significant difference compared with the irregular waves condition.The higher proportion of high-frequency energy,the better performance of wave attenuation of the breakwater.The wave transmission coefficient increases with the increase of periods of low-frequency bimodal spectra.On the premise of the same energy,wave transmission coefficient of bimodal spectrum waves is lower than wave transmission coefficient of irregular waves;the higher proportion of high-frequency energy,the bigger gap between wave transmission coefficient of bimodal spectrum waves and wave transmission coefficient of irregular waves.The breakwater mainly depends on energy attenuation to achieve wave-breaking effect on the condition of bimodal spectrum waves.The more contribution of low-frequency energy,the smaller gap between seaward mooring force of bimodal spectrum waves and seaward mooring force of irregular waves.Basically,the floating breakwater performs well on wave attenuation properties,the study of this paper provide a theoretical reference for the practical application of this new type floating breakwater.