A numerical assessment of the scale effects of a ship advancing through restricted waters

Restricted waters present several challenges for ship builders and operators. The proximity of the seabed and river or canal banks cause viscous effects to be more pronounced than in unrestricted waters. These effects do not follow a linear scaling law, which is typically assumed in terms of sinkage and trim. Moreover, the resistance of the ship is increased in a complex fashion, which has largely eluded researchers. The present study will aim to elucidate scale effects in shallow water performance predictions. Particular attention is placed on the form factor, wave resistance, and frictional resistance. Scale effects are confirmed in the two former parameters. Justification for the obtained results is sought in terms of flow properties. Specifically, the flow velocity and boundary layer thickness are examined in detail. The selected case-study reflects recent experimental work on the KCS hull form in restricted waters.