Computational Analysis On High-Order Waves And Wave Loads

At present, the calculations of wave forces on marine structures are confined to the linear and low-order non-linear wave theories, sometimes these are not satisfied with the requirements. With regard to marine platforms on North Sea, it especially could use eight-order non-linear wave theory on engineering calculations with the DNV criterions. The extreme ocean states are very important to ocean engineering. But the non-linear characters are very serious on extreme ocean states. Obviously, marine structures' output spectrums with all kinds of orders can be acquired by using the high-order wave programs. And these may be used to avoid sympathetic vibration on marine structures. Non-linear water wave dynamics and its engineering application become one of the frontier research fields drawing great attention recently.In essence, rather than solve the problem in the physical plane, where the shape of the free surface is unknown, L.W.Schwartz mapped the interior of each fluid cycle in the physical plane into an annulus of unit outer radius in the mapping plane according to the conformal transformation. And the perturbation theory is the main way of solving conformal parameters.In this paper, the chief work is to predigest the method of solving conformal parameters, which are non-linear equations. The perturbation parameters can be simplified by the math software of Mathematica or optimization algorithm and the computer-time is significantly reduced. Only input the ratio of fact depth to wave length into the programs, it can be simply acquired the conformal parameters. In the end, it is the computational analysis on high-order waves and wave loads in the fluid by using the programs.Based on the perturbation solution of non-linear waves by L.W.Schwartz, this paper provides a simple method, which can be used to calculate wave forces on marine structures. In this paper some examples are given and the computational results show the reasonableness of the formulations and the effectiveness of the method.