On Sloshing Force of Rectangular Tank Type LNG Carrier
摘要
Many researches have been carried out on sloshing forces of liquid in a ship tank. But most of them have focused on sloshing phenomena of a tank which has considerably large gas space. And only a few results have been reported about nearly fully loaded tanks. This may come from the fact that there are some internal structural members in usual tank tops which prevent the occurrence of large impulsive pressure. But in the case of a tank which has a large flat tank top without any internal members, it is considered important to predict the magnitude of impulsive pressure.In this report, authors present the results of model experiments focused on impulsive pressure of a nearly fully loaded tank. The experiments were carried out under the following conditions : Filling ratio : 90-98% tank depthKind of ship motion : Pitch, Roll, Surge and SwayMode of motion : Regular and Irregular Results are summarized as follows : (1) Even in the case of a tank filled up to more than 90%, considerably large impulsive pressure occurs at marginal part of tank top.(2) Considerably large impulsive pressure occurs in long period range in pitching and rolling.(3) Large impulsive pressure occurs in a very small area at each moment.(4) Pressure increases proportionally to the amplitude of motion in some cases, but it shows saturation in many other cases.(5) It is considered that the probability density function of impulsive pressure shows a distribution close to Rayleigh's and truncated exponential distributions in the case of regular motion.