Numerical modeling of ship motion in heavy sea conditions

The accurate determination of vessel motions and wave loads from the storm wave is one of the most difficult problems. Desktop computers are still not powerful enough for three-dimensional numerical simulation in time domain. In this article, the numerical model based on boundary element method (BEM) is used. For faster simulation the simplified interaction of a vessel and wave surface, and also condensation of nodal unknowns on a free surface is used. Against of other works on Numerical Wave Tank (NWT), free surface is not formed from the wave-maker moving, but is determined from solving separate problem. It is assumed that the ship does not change the form of a free surface. As result it is possible to divide a task: separately to determine parameters of wave movement and to calculate a motion of a ship on given waves. The 3D pitching simulation of a tanker is reviewed.