Abstract :
[en] The accurate prediction of ship performance in shallow water remains a critical challenge in naval architecture, as traditional methodologies primarily developed for deep water often fail to account for the complexities introduced by reduced water depth. Scale effects significantly impact hull-propeller interaction, resistance, wake dynamics, and propulsion efficiency, leading to discrepancies between model scale and fullscale predictions. This research investigates the scale effects on hull-propeller interaction in shallow waters through a combination of experimental towing tank tests and Computational Fluid Dynamics (CFD) simulations.
A series of systematic experiments were conducted using an Aframax hullform in shallow water conditions at the Flanders Hydraulics. Resistance and self-propulsion tests were performed at varying water depths and speeds to establish benchmark datasets. These experiments provided empirical insights into the effects of under-keel clearance on ship performance in shallow water conditions.
Parallel to the experimental work, a detailed numerical study was undertaken using CFD simulations to evaluate hull-propeller interactions across a range of Reynolds numbers. The numerical approach allowed for a rigorous investigation of wake field development, boundary layer growth, and thrust variations under restricted water depths. A comprehensive validation against experimental data was performed, highlighting the predictive capabilities and limitations of existing numerical techniques when applied to shallow water conditions.
Key findings from this study reveal that scale effects in shallow waters lead to significant deviations in nominal wake fraction, hull efficiency, and thrust deduction factors compared to deep water assumptions. The research identifies critical parameters influencing these discrepancies and proposes correction methodologies to enhance predictive accuracy. Additionally, a novel power prediction framework is introduced, refining the conventional ITTC extrapolation method to better accommodate shallow water hydrodynamics.
The outcomes of this study contribute valuable insights into ship design optimization, offering improved methodologies for resistance and propulsion assessment in shallow waters. These findings are instrumental for ship designers, regulatory bodies, and maritime engineers seeking to enhance vessel performance, operational efficiency, and environmental sustainability in shallow and confined waterways.
