Numerical And Experimental Study On The Interaction Between Waves And Two Floating Bodies

Based on the linear potential flow theory, the high-order boundary element method is adopted to establish the numerical model of the interaction between regular waves and two floating bodies in frequency domain. By comparing with published works, the validity of the numerical model is verified. Take rectangular boxes as examples, the model tests of the response of a single box and two boxes in regular waves are carried out, respectively. The effectiveness of the numerical model is verified further. In order to consider viscosity damping, free decay model test in calm water is carried out and the method of the calculation of damping was provided.For the multi-bodies system composed of two floating bodies, the hydrodynamic coefficients and the motion response of bodies are different from the case of a single floating body, because of the effect of the other body in system. The influence of hydrodynamic force of the other body should be taken into account. The solution of the interaction between waves and structures can be reduced to the solution of Laplace equation, which satisfies some boundary conditions and initial conditions. The diffraction potentials can be obtained by solving the boundary integral equations. Then based on the linear Bernoulli equation, the pressure on the body surface can be calculated. By integration of the pressure on body surface in calm water, the wave forces and moments could be calculated. At last, the motion response of each body in system could be identified by rigid body motion equation.By comparing with published works about hydrodynamic coefficients, exciting forces and motion responses, the effectiveness of numerical method is verified. And take rectangular boxes as examples, the model test of motion response of a single box and two boxes in regular waves are carried out, respectively. Because the model of the interaction between waves and floating bodies is established in the potential flow regime, the viscosity damping could not be considered. In order to consider viscosity damping, free decay model test in calm water is carried out. Because the radiation damping is included in the total damping obtained by model test, the difference between the total damping and the radiation damping calculated by numerical model can be used as the viscosity damping to be added in the motion response equation. The effectiveness of numerical model is further demonstrated by the comparisons with the results of model test, and the method to consider viscosity damping is reasonable.