ABSTRACT

This study presents results of an experimental study on three-dimensional sloshing phenomenon. The test rig used in this study was driven by six 15kw electric motors. The maximum load including dynamic load for this platform was estimated 4 tons. Six degrees of freedom of ship motion can be simulated with this platform. The 1/50 model of a 138,000 m3 LNG carrier was used to get the results. Irregular motions were simulated. The 24 pressure gauges were installed on the tank model. Each test lasted for a model time scale which is equivalent two 3 hour real sea motion. The 6 critical cases were tested after the screening tests. The 10 three hour full scale motion was tested for critical test. The results of impact pressure measurement were analyzed. The log-normal probability distribution function was employed to get the impact pressure which is equivalent to the 3 hour return period.

INTRODUCTION

The demand for natural gas is getting bigger and bigger. Natural gas supplied a quarter of the world energy consumption in 1999 according to statistics. Its consumption is expected to be increased from the environmental point of view. It is almost pollution free energy. As a result, the world fleet of LNG carriers has also increased accordingly. The efficiency of the transportation can be increased if designers come up with the idea of increased LNG tank size. This may, in turn, require technological advancement on several issues concerning draft limitations, increase of propulsion efficiency and maneuvering ability. During the operation in the ocean, sloshing can be one of the very important issues due to its substantial impact on the tank wall and structures. The sloshing phenomenon has drawn much attention due to practical as well academic interests for a long time in various engineering as well as scientific fields.

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