Abstract
This study investigated ship response statistics in waves evolving due to nonlinear quasi-resonant interactions. For that purpose, a nonlinear strip method, NMRIW-II (nonlinear motion in regular and irregular waves), has been extended such that nonlinear wave fields precomputed by the higher-order spectral method (HOSM) can be input. In the numerical simulation, the significant wave height and nonlinear order of the input irregular waves were varied to investigate the impact of wave nonlinearity on ship responses. Furthermore, a container ship and a wall-sided ship were used in numerical simulations to separate the nonlinearity influences attributed to the hull geometry and wave. The lengths, breadths, drafts, and water plane geometries were the same between these ships. The numerical results revealed that the body (hull-geometry) nonlinearity enhances the tail of the sagging moment peak probability distributions. Furthermore, an increase in large wave occurrence due to nonlinear quasi-resonant interaction was revealed to further enhances the tail of the sagging moment peak probability distributions.
