TIME SIMULATION OF WATER SHIPPING FOR A SHIP ADVANCING IN LARGE LONGITUDINAL-WAVES

The technique of time-domain numerical simulation for the occurrence o f water shipping on board in head waves is presented. The nonlinear ef fects of the large-amplitude motion are treated. These nonlinear facto rs include the effect of large wave amplitude, large ship motion, the change of hull configuration below the free surface and the nonlinear resultant wave. Therefore, the variation of the potentials and the hyd rodynamic coefficients for a ship at each time step must be carefully treated. While handling the determination of the instantaneous wave su rface around the ship hull, the complete incident, diffracted, and rad iated wave system is used rather than the incident wave only. The comp lexity of the ship speed effect on the related terms is also treated a t each time step, especially for the radiation problems. An experiment al setup is also designed to measure the motion response and the relat ive motion, and comparisons are made. The results show excellent agree ment and the validity of the theory is confirmed. The successful devel opment of the present technique can be extended to analyze the dynamic stability, capsize phenomena, and ship motion in irregular waves.