GFD simulation of the interaction of large-amplitude ship motion with the large deformation of the free-surface

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The technique to predict ship performance in actual sea condition is especially important for ship design. Waves always exist on the ocean surface and ships make large-amplitude, nonlinear motion. This gives serious influences on the economy and safety of sea transportation. The objective of this research is to develop such a technology to predict ship performance in waves by use of computer simulation based on fluid dynamics.The finite-volume method in the framework of the boundary-fitted coordinate system is chosen as a basical tool and the density function technique is introduced for the fulfillment of the free-surface conditions. With the combination of these technique the motions of largest amplitude such as pitching and heaving are simulated with sufficient degree of accuracy, having good agreement with experimental results. This method is extended to the motions in oblique waves and following waves. However, it is noted that the degree of robustness and stability is not very satisfactory. Therefore the overlapping technique is developed with the rectangular grids for the outer grids where waves are generated and the boundary fitted grids about a ship. With this new method all motions with six degrees of freedom are simulated. On the other hand another technique of numerically generating ocean waves is developed.The simulation technique is not fully developed to cope with any motion of a ship in any ocean circumstances. Some part is still left developed in the near future. However, the substantial architecture and components are completed by this research work.