Study of effect of rotational axis configurations on the slosh dynamics of the ship-mounted tank under different combinations of rotational excitations

Abstract

In maritime transportation systems, the stability and structural integrity of ship-mounted tanks subjected to sloshing phenomenon are critical due to economic considerations and to ensure ecological safety. During the voyage, the ships are subjected to external excitations, which induce sloshing in fluid in partially filled tanks mounted on the ship’s deck. This article investigates the effect of rotational axis configurations on the slosh dynamics of a 24,000 TEU water tank mounted on an Ever-Ace container ship. Sloshing phenomena caused by different combinations of piecewise sinusoidal rotational excitations have been compared. The fluid domain was simulated using ANSYS Fluent, coupled with transient structural analysis in ANSYS Mechanical, to analyze the structural integrity of the container. The fluid pressure loads were imported on the tank structure using a one-way FSI approach. The numerical results have been validated with the experimental data available in the literature. It has been found that the effects of viscous sub-layer are insignificant on the slosh dynamics of the tank. Moreover, the transient response of the air–water interface, impact pressure, and wall moment have been presented. Wave fluctuation is observed to be small when the axis of rotation is perpendicular to the free surface. Maximum impact pressure of 7 kPa has been observed for combination of roll and pitch motions. The range of amplitude of moment is maximum for combination of roll and pitch motions that varies from − 95.6 to 92.3 kN m. Furthermore, the frequency of the moment differed from the excitation frequency depending on the configuration of the rotational axis.