Prediction of the impact of biofouling roughness on a full-scale planing boat performance using CFD

Abstract

This study investigates the crucial role of surface roughness caused by biofouling in contributing to increased drag in fast planing vessels. Through rigorous computational fluid dynamics (CFD) simulations using a full-scale reference hull, the impact of surface roughness on planing hull performance is examined. The results show that heavy slime roughness on the hull surface causes a significant increase in total resistance, ranging from 10% at low speeds to 80% at high speeds. Skin friction was identified as the most affected component of resistance, with additional changes in residual resistance. Although the change in residual resistance is relatively small, they give rise to dynamic phenomena such as variations in pressure distribution, wave elevation, and wave making formation. The study also explores the influence of surface roughness on dynamic lift forces, observing an increase in upward friction forces but ultimately concludes that overall hull performance was hampered due to the disproportionately higher increase in resistance caused by roughness (biofouling). Changes in dynamic trim, dynamic sinkage, and dynamic wetted surface area due to this roughness are also discussed.