Cartesian-grid-based Computational Analysis for Added Resistance in Waves

An Euler equation solver based on a Cartesian-grid and non-uniform staggered grid system is applied to simulate and analyze the ship motion and added resistance in waves. Water, air, and solid phases are distinguished using a volume fraction function for each phase and in each cell. To capture the water interface, the tangent of hyperbola for interface capturing scheme is used with a weighted line interface calculation method. The volume fraction of a solid body embedded in a Cartesian-grid system is calculated using a level-set algorithm, and the body boundary condition is imposed using a volume-weighted formula. Numerical simulations for a Wigley III hull and an S175 containership in regular waves are carried out to validate the newly developed code and to compare the effects of numerical methods for calculating the added resistance. All the results are compared with experimental data, and a calculation for the KRISO’s very large crude carrier 2 is also performed. From the grid convergence test for incident wave generation and the added resistance calculation, the sensitivity of the grid spacing is investigated, and the minimum requirements for the number of gird points are suggested to reliably calculate the added resistance in waves.