Numerical Modelling and Study of Parametric Rolling for C11 Containership in Regular Head Seas Using Consistent Strip Theory

Abstract

SummaryIn this paper, a numerical model was proposed to simulate the parametric rolling of ships in head seas. The method was developed in time-domain based on strip theory, in which a consistent way of estimating the radiation forces was applied using impulse response function method. To take the coupling effect into account, the heave and pitch motions were solved together with the rolling motion. Also, the Froude-Krylov forces and hydrostatic forces were evaluated on the instantaneously wetted surface of the ship, in order to model the time varied restoring rolling moment in waves. Based on the developed numerical model, the parametrically roll motions of C11 containership was simulated. The influence of roll damping was investigated using two different methods, and the numerical results were compared with model tests. The comparative study shows that results obtained by the proposed method generally agree well with experimental data. Discussions and possible improvements of the current numerical model were also presented in this paper, with regard to the numerical deviation between the numerical and experimental results when the wave steepness was larger than 0.04.

Impact of Waves on Dangerous Stability of Vessels on the Oceanic Route

“…Although the Mathieu equation is linear, its solution is hard. Because the hazard stability of the ship is at high amplitudes, parametric rolling should be calculated from the nonlinear equation 11using numerical methods (Acanfora and Cirillo, 2017, Dunne and Wright, 1985, Faizarano and Mulk, 1994, Hu et al, 2017and Liaw, 1993. However, in order to solve the equation 11even when excitation moment from a regular wave, the amplitude of the metacentric height change hA and the phase angle h in the wave on which the vessel flows must first be calculated.…”

“…The rolling of the ship is influenced by the parameter and direction of the wave relative to the ship, the speed of the ship, the geometric parameters and the weight distribution of the ship, and additional damping devices, such as bilge keel. Dynamic stability of the ship is a complicated phenomenon and, therefore, in the literature, hazard stability analyzes are usually carried out from simplified mathematical models describing individual cases of rolling (linear and non-linear rolling, regular and irregular wave, constant or time-varying restoring moment), (Acanfora and Cirillo, 2017, Dudziak, 1988, Hu et al, 2017, PRS, 2020, Szozda, 1997, Wawrzynski and Krata, 2016. The article presents the problem of calculating rolling of ships of different models (linear and nonlinear, regular and irregular).…”

Determination of Linear and Nonlinear Roll Damping Coefficients of a Ship Section Using CFD

“…For the many years, parametric rolling was considered as an unlikely occurrence, but its importance started to be highlighted after the incident from 1998 when a post-Panamax container ship experienced extreme rolling due to this phenomenon. Since that time, a large number of efforts have been devoted to investigating the features of parametric rolling [1][2][3][4][5][6][7][8].…”