Scale effects on ship vertical force and trim moment in calm water

Predicting ship resistance with high accuracy is essential to reduce fuel consumption. Of the two currently available methods, extrapolation from models-scale using towing tank results shows high levels of uncertainty and while Computational Fluid Dynamics is a promising option to reduce this uncertainty, recent full-scale simulations show persistently high errors. Another way to reduce the uncertainty is to understand the scale effects and devise strategies to account of them. In this paper, we explore the scale effects on ship trim and sinkage through numerical simulations using viscous and linear scaling with three different turbulence models. We demonstrate that the scale effect on sinkage can be neglected. However, between Re = 10⁶ and Re = 10⁸, depending on the turbulence model, scale effects on the trim moment range from 15% to 27%, and differences in pressure coefficient on the hull can be observed between the different Reynolds numbers, especially around the aft of the ship of between 23.6% and 32.5%.