A study on prediction of ship maneuvering in regular waves

A simulation method is developed for predicting ship maneuvering in regular waves. Based on a two-time scale model, the total ship motion is divided into the low frequency maneuvering motion and the high frequency wave-induced motion. The maneuvering analysis is based on a MMG model which takes the mean second-order wave loads into account. In order to evaluate the second-order wave loads, a velocity potential is introduced and decomposed into a basic part and a perturbation part, which are related to the maneuvering motion and the wave-induced motion, respectively. The basic part is evaluated based on the double-body model with a trailing vortex sheet, while the perturbation part is solved via a time domain Rankine panel method. The effects of maneuvering motion on the wave forces are considered through the m-terms as well as the leading-order terms kept in the boundary conditions on the free surface. By using the proposed method, turning and zig-zag maneuvers of the S-175 container ship in regular waves are simulated. The predicted turning trajectories and 10 degrees/10 degrees and 20 degrees/20 degrees zig-zag maneuvers are compared with the experimental data, which show fairly good agreements. The drift forces and moment on the ship turning in waves are also discussed.