Numerical evaluation of turning performance of ships in regular and long-crested irregular waves

A maneuvering-seakeeping combined model is established to predict the maneuvering performances by using three-dimensional Rankine panel method and 4 degree-of-freedom Maneuvering Modeling Group model. The wave drift forces and moments in regular and irregular waves are pre-calculated via a near-field method considering the effect of the lateral speed. The wave drift forces and moments of some cases ( at Fn= 0.03, 0.06, 0.09, 0.12, 0.15; v/gL=± 0.01, 0, ± 0.02) are computed. They are used to build up a database, and loaded into maneuverability model, which is established by using the hydrodynamic derivatives from Planar Motion Mechanism test. In calm water, the discrepancies in advance and tactical diameter between the numerical results and the experimental data are found to be within 6.5%, affirming the effectiveness of the developed model. In irregular waves, the effects of different random seeds on the wave drift forces and moments are analyzed. The numerical results indicate that in both regular and irregular waves, the drift distances and directions are generally consistent with experimental data. Moreover, numerical results that take into account lateral speeds show even closer agreement with the experimental data. •The effects of lateral speeds on the wave drift forces and moments are analyzed.•The effects of different random seeds on the slow drift forces and moments are analyzed.•A combined model is established to rapidly predict the maneuvering performances of ships in waves.•The maneuvering performances are analyzed by loading the wave drift loads with or without the lateral speeds.