Numerical investigation on the lateral restriction effect in container ship squat based on the concept of normalised equivalent blockage

This study investigates lateral restriction effects on squat based on a novel approach to calculate blockage which is the concept of “normalised equivalent blockage ratio”,m _eq-norm . The Computational Fluid Dynamics (CFD) based study undertaken investigates the change in midship sinkage and trim of the KRISO container ship (KCS) in laterally restricted channels with varying channel widths and bank heights at different ship speeds and water depths. The CFD model has been validated against experimental data. Results demonstrate that the midship sinkage increases linearly with respect to m_eq-norm where the gradient depends on speed and water depth. However, trim remains relatively constant with respect to m_eq-norm throughout the cases tested. More importantly, it is shown that channels with different widths and bank heights, yet similar m_eq-norm, will result in similar midship sinkage and trim. Therefore, the m_eq-norm is a versatile and accurate approach to quantify the blockage of a channel and is suitable for implementation into real-time ship-handling simulator