Study of parametric roll in oblique waves using a three-dimensional hybrid panel method

Abstract

A reliable numerical tool for the prediction of the parametric roll is important in the development of the second generation intact stability criteria. The main difficulty of the prediction of the parametric roll comes from the significant coupling of the roll with other motions, especially the heave and pitch motions. In this paper, the numerical method for determining the parametric roll is studied and the results are benchmarked against the model test data. Firstly, a 3 degrees-of-freedom (DOF) time domain hybrid panel method is validated by experimental data in regular oblique waves and irregular head waves. Secondly, the verified 3DOF method is extended to a fully coupled 6DOF method with the course control. Finally, taking the C11 containership as the test case, the parametric roll in oblique waves is computed, and the effects of the surge, sway and yaw motions on the parametric roll are evaluated with the developed mathematical models. The results show that the effects of the surge and sway motions on the parametric roll is insignificant, while the effects of the yaw motion are more notable. The results of the roll amplitudes and the standard deviation of the roll angles show that the model based on 3DOF gives relatively conservative results, and can be directly used for the stability assessment of the parametric roll.