The Influence Of Viscosity On The Hydrodynamic Forces Of A Vertical Oscillating Ship Section

During the development of the sea trade, people have rather increasing demand for better ship designing methods. A higher speed can be achieved by optimizing the ship type, however, the increase of the forward speed results in a difficult problem that how to predict the hydrodynamic performance of high-speed moving body. In case of small-amplitude motion in the intermediate range of wave frequencies for which linear character is mainly represented, classical first-order potential-theory results are known to be reasonably accurate. A second-order analysis indicates that nonlinear effects are important in the high-frequency range. However, relatively few investigations of viscosity induced hydrodynamic nonlinear effects have been carried out.In this paper, the frequently used commercial CFD software FLUENT is used for numerical simulation and computation. Firstly, through wind tunnel experiments of slender body, some parameters in two equations k-ε turbulence model are selected, and the fluid field conditions are analyzed and compared. Afterwards, the numerical simulations and computations for two dimensional sections validated the feasibility of two equations k-e turbulence model on simulating and computing free-surface unsteady flow problems. After comparing and analyzing the hydrodynamic performance of some ship forms, such as rectangle section form, U-form, deep V-form, semi-submersible bow section form, etc., the author compared the results of numerical simulations and computations with potential-theory results under corresponding conditions. Therefore including the viscous effect on hydrodynamic forces on sections. For small-amplitude oscillation of regular hull section, the results obtained by potential-theory are close to viscous numerical results, the difference between these two models get large as the amplitude increase. For semi-submersible bow section form, that...