Study On Wave Attenuation Performance Of Double Row-Pontoon Breakwater

The exploration of the ocean has already stepped into the deep sea.The floating breaker which can decay the wave is needed to ensure the safety of exploring process.In practical engineering,two commonly used methods are adopted to enhance the wave attenuation effect of the pontoon breakwater.One method is to enlarge the width of the pontoon in the wave direction,and the other one is to increase the draught by adding the auxiliary components to the bottom of pontoon.However,these methods are difficult to implement in practical.Thus the Double row-pontoon breakwater is proposed in this dissertation to solve the problem mentioned above.The wave attenuation performance of the new type of floating breakwater is studied experimentally and numerically.Firstly,the physical model tests and AQWA simulation are carried out to study the transmission coefficient of the Double row-pontoon and the pressure distribution on the pontoon under regular waves.The research focuses on the affection of the depth of water,wave period,distance between two pontoons and relative pontoons draught on the transmission coefficient of the Double row-pontoon.The results of the experiment and simulation indicate that the ideal wave attenuation performance will be gotten when the transmission coefficient of the Double row-pontoon breakwater is from 0.3 to 0.8under the wave period from 0.81 to 1.03 s.The transmission coefficient increase along with the increasing of the water depth or the wave period.The transmission coefficient decrease along with the increasing of the relative pontoons draught.And the transmission coefficient increases first then decreases with the increasing distance between two pontoons.Then an artificial neural network model is built to describe the relationship between the wave attenuation performance of Double row-pontoon and its restriction factors,which can be used for the prediction of transmission coefficient.Compared with the transmission coefficient of single-pontoon,Double-pontoons and Pontoon-board under the same wave conditions,the prediction result indicates that the wave attenuation performance of the new structure proposed in the thesis is better.