Numerical simulations on radiation problems of vessels for both cases of moving with and without speed are carried out. A numerical wave tank is established to simulate vessel oscillating in waves based on CFD theories. An approach to evaluate and analyze hydrodynamic coefficients is introduced to deal with the measured forces acting on moving vessels. The comparisons of the present results and that of potential flow theories and experimental data are conducted. They are all in good agreements.
Accurate evaluation of ship hydrodynamic coefficients on radiation problems of moving vessels is of great significance for predicting ship hydrodynamic performances in waves. Up to now, there are many theoretical methods to predict ship motions, such as strip theory (Korvin-Kroukovsky, 1955), slender body theory (Faultisen, 1991), 3D potential theory in frequency/time domain (Dai and Duan, 2002), and some related modified theories and methods (Liu and Miao, 1986). Most of the theories are established on linear potential methods, which can not consider the effects of viscosity and non-linear physical characters due to the limitation of linear assumption. Especially for roll motion, great errors may occur. So it is helpful to seek new approaches to deal with naval architecture and ocean engineering problems. Currently, with the development of technique of computer and numerical calculation, Computational Fluid Dynamics (CFD) is advancing and making the numerical simulation a critical approach for research. More detailed fluid information around ship can be obtained by using CFD theories in the ship hydrodynamic research. Compared to physical experiment, it has the virtues to be easily controlled and realized with low cost and without scale effects. So that it is being widely applied in many aspects of ship hydrodynamic research (Korpus and Falsarano, 1997; Chang et al, 1995; Lin et al, 2006).