Investigation of Coupled Motions of Two Ships Sailing Parallelly in Waves Based on Translating-pulsating Line Source Green's Function

Within the framework of three-dimensional frequency-domain potential flow theory, the translating- pulsating source Green's function is applied to construct the boundary integral equation (BIE), and a computational model is established for the coupled motions of two ships sailing parallelly in waves. In order to avoid numerical instability, influence coefficients in the BIE are evaluated based on an analytical formula of the Green's function distributing on the horizontal line segment (named as translating-pulsating line source Green's function), and a computer program is developed based on this method. The numerical algorithm is validated through the simulation of motions of a single ship. Coupled motion responses of a frigate and a supply ship sailing parallelly in waves with or without stagger are calculated and analyzed respectively. Numerical results show that the present method is of better accuracy and stability than the pulsating source Green's function method and the translating-pulsating source Green's function using numerical integration formula. Influence of hydrodynamic interaction on the smaller ship is found to be more noticeable, which becomes weak with the increase of the longitudinal distance between two ships. © 2022, Editorial Office of Ship Building of China. All right reserved.