A numerical study on coupled sloshing and ship motions of a liquefied natural gas carrier in regular and irregular waves

Abstract

This article presents a numerical study of the coupled ship motions and tank sloshing of a liquefied natural gas carrier. To solve this coupled problem, we have developed a time-domain numerical method. The method combines a ship motion solver based on strip theory and a computational fluid dynamics sloshing solver. The method has been applied to a liquefied natural gas carrier model to investigate the coupling effect in regular waves. Simulations for four different loading conditions were carried out, and the results of ship motion response amplitude operators and free surface movement amplitudes were presented in frequency domain. The coupling effect on ship motions and sloshing has been discussed. Based on the assumption of linearity of ship motions and wave, the authors used the ship motion response amplitude operators (with coupling effect) obtained in regular wave conditions to generate ship motion time histories in irregular waves. Sloshing in tanks was then simulated by using the ship motion time histories in irregular wave conditions. The calculated impact pressure time histories were analyzed by using the exceedance probability function.