The Influence of Roughness Change on Ship Resistance in CFD Simulations

Abstract

The biofouling of ship hulls has a significant impact on both the environment and the ship. A negative effect on the environment is manifested by an increase in pollution with greenhouse gasses and disrupting the ecosystem by translocating microorganisms, sea plants or animals from one place to another. Biofouling film which appears on the immersed hull part through the years increases surface roughness and therefore induces a streamlines disturbance and together with increased wet surface affects the increase in total resistance. As a result of greater total resistance, a larger amount of fuel combusts over time, thus greenhouse emission is being increased. A numerical model based on Reynolds Averaged Navier-Stokes (RANS) equations with incorporated different roughness effects as equivalent sand grain roughness height in one Computational Fluid Dynamics (CFD) software has been conducted in this paper. Simulation has been applied to one bulk carrier and represents the effect of dry-docking the ship after several years in operation and treating the hull with high-performance coat such as self-polishing coating (SPC) or silicone- and fluorine-based fouling coatings (FRC).