Experimental Investigation On Influence Factors Of Twin-Pontoon-Plate Floating Breakwater

In recent years, with the construction of more deepwater sea ports and the vigorous development of marine aquaculture, as well as the emergence of large numbers of yacht marinas and bathing beaches, floating breakwaters have attracted more and more attention as artificial wave attenuation facilities. Compared with the traditional gravity breakwater, the floating breakwater has several distinctive superiorities, such as simple structure, aesthetically pleasing, low investment, environmental friendliness, strong adaptability to water depth and subsea conditions, convenient for construction and demolition, et al. However, the transformation from research to practice of floating breakwaters is restricted by several shortcomings. For instance, they are inefficient for long wave attenuation, and their durability and security are not guaranteed. Therefore, it is significant to seek a reasonable floating breakwater structure with obvious effect of wave attenuation and reliable safety performance.An innovative floating breakwater structure, namely twin-pontoon-plate type, is presented in this paper, and an experiment is carried out for regular waves to investigate the influence factors on wave attenuation, motion response and mooring force of the floating breakwater. The experimental results illustrate how the hydrodynamic behaviors are affected by several factors, including the relative width of breakwater, the horizontal plate number, the distance between horizontal plates, the stiffness of mooring chain and the relative wave height.The experimental results show that the twin-pontoon-plate floating breakwater proves more efficient for intercepting wave than the twin-pontoon floating breakwater, especially for long waves, and the transmission coefficient decreases about0.4at most. Furthermore, the motion stability is improved, especially the heave and roll motion displacement amplitude decrease obviously. Consequently, it’s of great practical significance for the innovation of this new type floating breakwater. The mooring force, nevertheless, increases so obviously that the safety performance of mooring system should be paid more attention.It is also found that different structure parameters and wave conditions have definite influences on hydrodynamic characteristics of floating breakwaters. In the range of experimental research, the relative width of breakwater and the horizontal plate number are main factors to affect the hydrodynamic behaviors, and the influence of the distance between horizontal plates proves less obvious by comparison. However, the stiffness of mooring chain mainly impacts on mooring force and the relative wave height has significant influences on motion response and mooring force. The achievements of this paper can be used as theoretical reference for the engineering practice of this new type floating breakwater, and then promote the application of floating breakwaters in coastal engineering in china.