CFD verification and validation of added resistance and seakeeping response in regular oblique waves with varying wave length

The importance of CFD is increasing in marine hydrodynamics in studying seakeeping and added resistance of ships. While extensive numerical studies have been reported for various ships in head seas in the literature, much fewer CFD studies are found for oblique waves, which in practice is very important in, for instance, estimating required power and manoeuvrability of ships in realistic sea states. In this paper, the added resistance and motion responses for the KCS container ship in regular waves are studied and validated systematically for five wave headings and six wavelengths using CFD. The ship is free to heave, pitch, and roll. Implementations to the commercial CFD code are made to fix the yaw and surge motions. Extensive verification of the CFD model finds the estimated spatial and temporal discretization errors to be less than 5 %. Results of the verified CFD model are compared with up to three sets of experimental data sets, Potential Flow (PF) and existing CFD results from the literature. In general, the present CFD results show significantly better agreement with the experiments than previously published CFD results. The agreement between the present CFD model and experiments is better for the headings, where the uncertainties of the experiments are smallest. Present CFD results confirm previous published numerical findings that the experimental roll motion is excessive for the 45 ◦ heading. and validation of seakeeping responses and added resistance of the KCS container ship in regular oblique waves by using a CFD approach with turbulence modelling. Convergence studies of both the temporal and spatial discretization errors are presented. Discussions are made to determine affordable time steps and mesh sizes while to keep the discretization errors acceptable. The yaw and surge motions are constrained by user-implementations in the commercial software, which consist of additions of springs and concentrated forces/moment to cancel the fluid forces and moments. The mesh and time step convergence studies shows that the sum of the spatial and temporal discretization errors for an affordable calculation is less than 5 %, which is smaller than the average standard deviation of the experiments by (Sanada et al., 2021). A study of