Multi-domain Higher-order Boundary Element Method Based on Vertical Integral Time Domain Green's Function and Its Application in Calculation of Added Wave Resistance

Based on three-dimensional potential flow theory in the time domain, a multi-domain higher-order boundary element method is established to calculate ship motions and added resistance in waves. In the outer domain, the time domain free surface Green's function method is applied. Integral of Green's function over the panels on the control surface are divided into two parts: vertical integral and horizontal integral. A new analytical expression of the kernel function is derived for the vertical integral, while the horizontal integral is dealt with numerical discretization. Convergence and efficiency of the calculation are improved significantly. In the inner domain, Rankine panel method with nonlinear free surface boundary condition is applied, and coupled solution of the inner and the outer domain is obtained. Ship motions are obtained by solving motion equations in the time domain and the second-order force is obtained with near field pressure integral method. Motion and added wave resistance of a math ship model Wigley III are calculated with the present method. Results are compared with experimental data and other researches, which validate the accuracy and stability of the present method. Added wave resistance is calculated on a real hull form S175 advancing in regular and irregular waves respectively and compared with experimental data and other researches, which prove the advantage of the present method in accuracy, stability and efficiency. © 2021, Editorial Office of Ship Building of China. All right reserved.