Numerical study on oblique sailing hydrodynamic derivatives of KVLCC2 under different loading conditions

Abstract As a commonly encountered condition during ship navigation, oblique sailing motion holds significant relevance for enhancing the accuracy of ship manoeuvrability predictions due to its distinctive hydrodynamic characteristics. In this study, based on Computational Fluid Dynamics (CFD) simulations, the standard ship model KVLCC2 is selected as the research subject. Comparative simulations are conducted for both ballast and fully loaded conditions at 50% of the design speed. A series of drift angles are prescribed, and the viscous flow field under oblique sailing conditions is simulated using STAR-CCM+ software. By comparing the simulation results with towing tank experimental data, the discrepancies in force and moment coefficients are found to be minimal. Specifically, the relative error of the longitudinal force coefficient is less than 5%, thereby validating the accuracy of the established numerical model. On this basis, hydrodynamic force and moment coefficients are fitted using the least squares method to obtain polynomial expressions of the oblique sailing hydrodynamic derivatives under varying loading conditions and drift angles, providing a reference for the quantification of manoeuvring hydrodynamic derivatives.