Restricted water effects on the prediction of berthed ship-passing ship interaction forces and moments using an inviscid and viscous numerical models

Most currently available empirical and semi-empirical methods to quickly predict the interaction forces and moments on a berthed ship due to a passing ship are based on scenarios with low under keel clearances and wide channels where the effects of the lateral banks are negligible. However, many ports are operating at low under keel clearances with narrow channels. The effect that low under keel clearances and narrow channels have on the magnitude and form of the interaction forces and moments have been demonstrated in past published work. Hence, it is important to account for these effects in prediction techniques.

This paper presents the verification and validation of two Computational Fluid Dynamics (CFD) numerical models; an inviscid double body method and a viscous double body method; used to predict the interaction forces and moments imparted on a berthed ship due to a passing ship. Inviscid or potential methods have been shown by past authors to give good approximation of the interaction forces and moments imparted on a berthed ship. However, many of these methods have not been validated against ship interaction scenarios with low under keel clearances and narrow channels. In this paper the results from inviscid and viscous double body models have been compared to physical scale model experimental measurements conducted for a range of passing ship speeds and water depths in a wide and narrow channel cases. The inviscid and viscous double body models were shown to correlate well with the experimental data for the larger water depth to draft ratios for the wide channel. However, for the narrow channel with water depth to draft ratios below 1.10 the correlation with the experimental results varied. For the cases presented, the inclusion of viscous effects, in general, did not improve the correlation with the experimental measurements.