The impact of roughness on the resistance of full-scale ships

Abstract This study aims to explore the impact of hull roughness on ship resistance, which provides a reference for enhancing the operational efficiency and energy-saving levels of ships. Initially, the development and accuracy of Computational Fluid Dynamics (CFD) numerical simulations are elucidated through literature, and the current state of research on hull roughness by scholars both domestically and internationally is introduced. Subsequently, taking the 2000 TEU container ship SITCCAGAYAN as the object of study, a CFD simulation is performed based on the unsteady Reynolds-averaged Navier-Stokes equations in Star CCM+ software. An improved wall function method and roughness function are used to design the simulation experiments, conducting the resistance prediction under various conditions, including the fully smooth hull, fully rough hull, and different levels of roughness at various parts of the hull. The experiment, based on results such as the increase in resistance, roughness impact factor, and roughness Reynolds number, demonstrates that the surface roughness of the hull significantly affects the magnitude of ship resistance. An increase in local and overall roughness leads to an increase in total resistance, but the roughness at the bow part of the ship has the greatest impact on resistance.