Non-Linear Motion Response Simulation of Floating Vessels in Waves

The subject of this thesis is the prediction of non-linear motions of floating bodies subjected to waves by a time domain method. Two steps are followed in the research, the first one consists of developing and applying a method able to calculate the hydrodynamic forces associated with non-linear unsteady motions in the time domain, since the ordinary frequency domain hydrodynamic coefficients are restricted to sinusoidal motions. Once this method is validated one non-linear term is studied and introduced to the motion equations. The non-linearity arises from the evaluation of the hydrostatic forces and moments taking into account the instantaneous wetted surface. The linear free surface elevation on the sides of the body contributes to the wetted surface. All time domain numerical results are compared with the corresponding linear frequency domain results, thus it is easy to verify improvements or discrepancies predicted by the non-linear model