A computational fluid dynamics simulation method is developed to predict the heave and pitch motions of ship in head waves. A numerical approach of wave-generation method by defining inflow boundary conditions is employed to generate the regular and irregular waves, and the outgoing waves are numerically dissipated inside the artificial damping zones. To predict the motions of ship in waves, the kinematics equations of rigid body and the Reynolds Averaged Navier-Stokes (RANS) equations describing the flow around the ship are solved simultaneously. The method is applied to simulate the motions of WigleyIII in regular and irregular waves, and the pitch and heave transfer functions are obtained. The simulation results are examined by the comparisons with the results of modified strip theory method and experimental data from Delft University of Technology, and in general agree well, which demonstrate the ability of the present method to assess seakeeping characteristics.
An accurate prediction of ship responds in waves are important for seakeeping design, the usual methods to predict the seakeeping characteristics are experimental test and theoretical calculation. The full-scale experimental test is always limited by the test conditions and the obtained data from an existing vessel may not always be available for other ship. The model test requires experimental facilities, and often be expensive and time consuming. Generally speaking, there are two important problems for seakeeping research, generating wave environment accurately, and simulating the large amplitude motion. In recent years, the tendency of the research of ship response in wave develop from frequency domain to time domain, linear to nonlinear and potential method to viscous method, with the development of viscous flow theory and computer technology, the Computational Fluid Dynamics (CFD) method has been applied to investigate ship characteristic more and more widely.