Hydrodynamic interactions between two ships travelling or stationary in shallow waters

In this paper, a boundary element programme MHydro, which is based on 3-D Rankine source method, was developed to investigate the ship-to-ship interaction problem. The method developed considers both stationary and forward speed cases. A new radiation condition, which takes Doppler shift into account, is imposed on the control surface. For the stationary case, the validations were carried out both in head sea and beam sea conditions. The experimental measurements, as well as the published numerical results, were used for the comparison. For the ship-to-ship with forward speed case, we validated our method through the experimental tests. Good agreement was achieved except the roll motion. The hydrodynamic coefficients and wave excitation forces were investigated and a very large sway force was predicted when the transverse distance between two ships equalled to the wave length. The wave elevations in the gap were also calculated. Discussions are highlighted on the shallow water effects.