A Hydrodynamic Numerical Study On Twin-Pontoon Type Floating Breakwater

Floating breakwater compared with traditional breakwater have some advantages, such as:easy to apply in the soft soil sea bed, having less environmental impact on bays and estuaries, keeping offshore water-exchange, and simple structure, inexpensive cost, convenient construction, easy relocation and so on. In this paper, based on previous research results, I proposed a Twin-Pontoon floating breakwater structure, and studied the hydrodynamic characteristics.Based on linear time-domain theory, the integral function is established, and solved by the boundary element method. By Newton second's law, the time-domain motion equations of the mooring chain restrained Twin-Pontoon floating breakwater are built and solved by the fourth order Runger-Kutta method. According to the force balance principle to establish the anchor force equations on the basis of the Lumped-mass method and using iterative numerical to solve the anchor force; Application of the model to study the Twin-Pontoon floating breakwater hydrodynamic characteristics. First of all, calculate the Single-Pontoon floating breakwater's hydrodynamic characteristics by application the mathematical model, and finding it good agreement with experimental results; afterwards, calculate the Twin-Pontoon floating breakwater of the hydrodynamic characteristics. Get the transmission coefficient, movement amplitude and chain force in different wave height, different wave period, different spacing pontoon and different displacement. By analyzing the data find that the space of the Twin-Pontoon floating breakwater has greater influence on transmission coefficient, chain force and movement amplitude. The numerical model of this paper, the Twin-Pontoon floating breakwater that the space of the pontoon is 0.25m has the best performance; Floating breakwater's structure has more obvious influence to anchor force and movement amplitude When the incident wave's period is greater.