Numerical simulation of nonlinear waves and ship motions

A numerical method is presented for simulating the behaviour of large amplitude nonlinear free surface waves including wave breaking. Various initial conditions are given and the subsequent surface profiles are calculated by a time stepping simulation. The flow field is solved as a boundary value problem for the velocity potential using a complex variable method based on the Cauchy integral theorem. Waves of varying shape, height, and length are investigated to determine the parameters necessary for wave breaking and the resulting fluid velocities. The technique has proven to be very accurate and stable. The method is extended to predict the motions of a two dimensional floating body in large amplitude seas accounting for non-linear effects and fluid-body interaction. The presence of singularities at the free surface intersection points was found to severely limit accuracy of the solution and attempts to overcome this problem are discussed. An extension to handle three dimensional ships is also described.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat