Multi-degree-of-freedom motions and effect on rolling dynamics of damaged ship in oblique waves

The study investigates the motions of a damaged ship in regular quartering waves with multiple degrees of freedom and their impact on rolling dynamics using computational fluid dynamics simulations. To ensure the accuracy of wave propagation, a wave-making method is extended by combining the inlet boundary and momentum source technique to generate quartering waves. A dynamic mesh strategy based on the motion decomposition concept is employed to efficiently update the mesh following the ship's motions. Additionally, the rolling hydrodynamic coefficients of damaged ship in forced motion are identified using support vector regression. The computation accuracy is verified by the experimental data pertaining to a damaged ship motion in quartering waves and calm water. Results from simulations of the ship's free and forced motions near the resonant roll period indicate that the wave direction significantly influences the roll response compared to other motions. Sway and heave motions play a crucial role in the rolling hydrodynamics of the damaged ship, with the rolling hydrodynamic coefficients varying notably with changes in the phase difference between sway, heave, and roll motions. These variations in damping coefficients result in significant differences in the roll response of the damaged ship in bow and stern quartering waves.