Prediction of Wave-Induced Motions and Loads of Ships With Forward Speed by Matching Method

A novel matching method has been developed to solve the wave-induced motions and loads of ships with forward speed. The fluid domain is divided into two subdomains by a cylindrical control surface: an interior domain and an exterior domain. Unlike the conventional domain decomposition strategy, the control surface is meshless in present method, on which the physical quantities are expanded into Fourier-Laguerre series. Based on forward speed Green function, the source distribution method is adopted to solve the exterior domain. The calculations of boundary integral equation about forward speed Green function over the control surface are performed analytically, and the solution of exterior domain provides a Dirichlet-to-Neumann (DN) relation on the control surface. In the interior domain, the boundary value problem is solved by Rankine source method. In order to be consistent with exterior solution, the control surface is kept meshless. The ship hull is discretized into constant panels. The free-surface is discretized into cubic B-splines to represent the high-order derivatives of velocity potential precisely. Then, the DN relation is used to close the equation system established in the interior domain. Comparisons with known experimental measurements show that the calculations achieve good accuracy. Furthermore, the influences of numerical method used in the exterior domain are described.