CFD Simulation for Green Water Events on KFPSO Using Design Wave Methods

Under extreme environmental conditions, large relative motions of a floating production storage and offloading unit (FPSO) can lead to green water events, which poses a significant risk of structural damage to topside equipment and deck structures. In this study, the green water height was quantitatively evaluated under design wave conditions using computational fluid dynamics (CFD) simulations. First, the CFD simulation setup was validated by comparing the relative wave elevations obtained from both experimental and CFD results. Subsequently, three types of design waves – regular design wave, New Wave, and most likely extreme response (MLER) wave - were employed to investigate the characteristics of green water at 71 deck positions through local motion response and wave pattern analysis. The maximum height of green water on the deck was observed when the relative wave motion exceeded the deck level through the bow flare, with the highest values occurring under the regular design wave condition, followed by the MLER and then New Wave conditions. It is concluded that the MLER method, based on the relative wave motion RAOs, offers a superior design wave approach for green water estimation compared to the regular design wave and New Wave methods.