CFD Prediction of Ship-Bank Interaction

Abstract

Ships operating in different shallow-water areas are at risk of grounding due to squat, heel and wave-induced motions. The paper aims not only at assessing the ship squat in any bathymetry, but also to reveal the waves influence on the environment. A 3D numerical model for predicting ship resistance in confined waters by taking the ship sinkage into account is proposed. A time-domain model is used to predict unsteady squat and dynamic acceleration effects for a vessel travelling in non-uniform water depth. A quasi-steady approach where the prediction at each time step is based on steady-state heave force and pitch moment in uniform water depth is used. Resistance, sinkage and trim, the free-surface elevation as well as the wake flow structure are considered in the ship performance analysis. The results show the wave pattern in the subcritical, critical and supercritical regions. The total resistance/drag is calculated at various ship speeds in shallow water using CFD and compared with the calculated deep water resistance. Attention is paid to the verification and validation based on a grid convergence study, as to the exploration of the modelling error in RANS computations to enable more accurate and reliable predictions of the bank effects.