NONLINEAR SHIP MOTIONS

A nonlinear numerical method has been developed to compute motion resp onses for a ship traveling in steep ambient waves. The method is based on an approximate theory and is an extension to a well-established li near time-domain numerical method. The nonlinear solution is found to be greatly improved over the classical linear and quasi-nonlinear solu tions, in comparison to experimental measurements for conventional com mercial ships. Through this study, it is also demonstrated that the fr ee surface hydrodynamic nonlinearities are at least as important as, i f not more than, the hydrostatic and Froude-Krylov nonlinearities. Sta bility, consistency and convergence for the nonlinear method are also addressed.