Coupling actions between sway and roll motion responses of the ship with sloshing inside

The coupling actions between the sway and roll motion responses of a ship with sloshing inside are investigated according to experimental measurements and numerical simulations. The increased coupling actions between sway and sway motion responses can be observed after considering the internal sloshing flow actions. When the ship is empty, only the sway motion response around the roll resonant periods can be affected by the roll motion coupling actions, while the sway motion coupling actions cannot affect the roll motion response. After considering the internal sloshing flow, the discrepancy between the sway-roll system and individual roll or sway system can be observed not only around the sloshing natural periods but also around the resonant sway and roll resonant periods and sloshing natural periods. It includes both the sway and roll motion responses. Finally, the influence of incident wave amplitudes and filling conditions are also discussed in this study.