A multi-domain method incorporated with higher-order boundary element method is proposed to calculate large amplitude ship motions with high accuracy and stability, in which the Rankine panel method and free surface Green's function method are applied in the inner and outer domain, respectively. The boundary conditions in the inner domain consider nonlinear items including incident wave potential and elevation, by which wave-body interactions are analyzed influenced by incident waves. Large amplitude ship motions, such as parametric roll of C11 container ship, are then simulated by this method and significant effects of incident waves on wave-body interactions are observed, which validates the accuracy and stability of present method.
Nowadays, hydrodynamic analysis models for ship advancing in waves are developed from linear, micro-amplitude forms to nonlinear, largeamplitude forms. The multi-domain method based on potential flow theory is gradually employed in nonlinear time domain hydrodynamic analysis and ship motion calculations. This method combines the advantage of the Rankine panel method (RPM) used in the inner domain and free surface Green's function method used in the outer domain, which satisfies the far-field radiation boundary condition automatically and adopts nonlinear items on free surface and ship hull boundary condition flexibly to improve the accuracy and stability of calculation.
Zhang, Lin and Weems (1998) applied the multi-domain method in ship motion calculation and established hybrid boundary integral equation. Lin and Yue (1990) developed software LAMP for nonlinear hydrodynamic calculation. Duan and Dai (2001) used multi-domain method to calculate ship motion with control surface near ship hull. Liu and Papanikolaou (2011) proposed a hybrid Green's function method in earth coordinate system to compute ship motions and added wave resistance. Tang and Zhu (2014) studied ship motion in waves with/without speed by a hybrid Green's function method. Chen and Liang (2016) established a multi-domain method with non-grid in the outer domain to calculate hydrodynamic coefficients and motions.