Seakeeping prediction of KVLCC2 in head waves with RANS

The present work is devoted to the prediction of added resistance and ship motion of KVLCC2 in head waves. Systematic validation and verification of the numerical computation demonstrate that reliable numerical results can be obtained in calm water as well as in head waves. The numerical results are analyzed in terms of added resistance, ship motions and wake flow. Both free to heave and pitch and fixed model are studied to investigate the contribution to added resistance from ship motion at different wavelengths, and the results show that ship motion induced added resistance is negligible when the wavelength λ < 0.6 Lpp. The comparison with theoretical calculation based on strip theory and experimental results shows that RANS predicts the added resistance better in all wavelengths. Ship pitch and heave motion in regular head waves can be estimated accurately by both CFD and strip theory. Finally, wake flow at the propeller plane in waves is discussed, and the numerical results show that the change of axial velocity due to one studied incoming head waves is at most over 30% of the ship forward speed.

► CFD method could predict the added resistance with higher accuracy in all wavelengths than theoretical methods ‘REM’ based on strip theory.
► CFD simulation did not show advantage over strip theory in estimating the ship motions.
► The variation of axial velocity due to one studied incoming head wave at propeller disc is more than 30% of ship forward speed.