A study on the coupling effect between sloshing and motion of FLNG with partially filled tanks

Abstract

This paper discusses the coupling influence of floating LNG (FLNG) motions with internal liquid sloshing. Model experiments were performed in an ocean model basin, and results were compared with numerical calculations. The FLNG model used in our study had 6 square tanks. In order to verify the liquid cargo effect, the FLNG model was tested under two conditions: a liquid-cargo condition and a fixed solid-cargo condition. As for filling level, there were three loading conditions (15%, 50%, and 90% filled). Our numerical scheme solves internal liquid sloshing using a three-dimensional finite difference method, and ship motion by potential theory. The sloshing effect was computed by the time-domain coupled simulation. We obtained good agreement between experimental and numerical results even at the near-natural frequency of sloshing. In both experimental results and numerical simulations, the effect of internal liquid is significant for sway and roll motion. Furthermore, the internal free surface motions obtained by the experiments and numerical simulations showed similar non-linear free surface behavior in the case of low filling.

A Methodology to Assess the Sloshing Effect of Fluid Storage Tanks on the Global Response of FLNG Vessels

“…They investigated dissimilar working conditions and the influence of the liquid height in the tank, tank size, and the wavelength ratio of the incident wave on the vessel motion. Kawahashi et al [22] performed tests to investigate the coupling effect of FLNG motions with internal sloshing flow. This test included an FLNG model equipped with six square tanks under a fixed solid-cargo condition and a liquid-cargo condition.…”