Numerical Analysis of Large-Amplitude Ship Motions Using FV-based Cartesian Grid Method

Abstract

A finite-volume (FV)-based method on a non-uniform Cartesian grid with staggered arrangement of variables is applied to simulate and analyze large-amplitude ship motions. The wave-body interaction problem is considered as a multi-phase problem with water, air, and solid phases. Each phase is identified by a volume-fraction function in each cell. In order to capture the interface between air and water, the tangent of hyperbola for interface capturing (THINC) scheme is used with weighed line interface calculation (WLIC) method. The volume fraction of a solid body embedded in a Cartesian grid system is calculated by a level-set based algorithm, and the body boundary condition is imposed by a volume-weighted formula. Wave excitation force and moment and hydrodynamic coefficients are validated for a Wigley III hull. Numerical simulations for the ship motion in linear waves also have been carried out to validate the newly developed code. The computational results for the Wigley III hull with different forward speeds are compared with experimental data. To demonstrate the applicability of the method for highly nonlinear wave-body interactions such as green water on the deck, numerical analysis of the large-amplitude ship motion of an S175 containership is conducted.lem with water, air, and solid phases. Each phase is identified by a volume-fraction function in each cell. In order to capture the interface between air and water, the tangent of hyperbola for interface capturing (THINC) scheme is used with weighed line interface calculation (WLIC) method. The volume fraction of a solid body embedded in a Cartesian grid system is calculated by a level-set based algorithm, and the body boundary condition is imposed by a volume-weighted formula. Wave excitation force and moment and hydrodynamic coefficients are validated for a Wigley III hull. Numerical simulations for the ship motion in linear waves also have been carried out to validate the newly developed code. The computational results for the Wigley III hull with different forward speeds are compared with experimental data. To demonstrate the applicability of the method for highly nonlinear wave-body interactions such as green water on the deck, numerical analysis of the large-amplitude ship motion of an S175 containership is conducted.