Effects of sloshing on the global motion responses of FLNG

摘要

Effects of inner-tank sloshing on the global motion responses of a floating liquefied natural gas (FLNG) vessel has been investigated through a series of model tests. Decay tests with the FLNG vessel subjected to a forced excitation in heave, roll and pitch motions in still water were carried out. The FLNG vessel was also subjected to band-limited white noise wave excitations under head, quartering and beam sea conditions. Three filling levels of 20%, 40% and 60% were included. To clarify the influence of the inner-tank sloshing, model tests were also carried out for the FLNG vessel with the inner-tank liquid treated as frozen mass (substitute the inner-tank liquid with equivalent solid weight) corresponding to each filling level. Based on the experimental results, we conclude that the effects of the inner-tank sloshing on the responses of FLNG are sensitive to wave excitation frequencies. The inner-tank sloshing can obviously affect the wave frequency motions of the vessel, in particular the roll motions can be most pronouncedly affected, while it is insignificant on low frequency motions. In addition, the influence of the filling levels has also been investigated through the comparison of the three filling conditions.