Numerical simulation of sloshing in a rectangular tank under combined horizontal, vertical and rotational oscillations

Abstract

The sloshing of fluid in an enclosed tank due to regular excitation in the horizontal, vertical and rotational modes is investigated through a numerical model. Finite element method with cubic spline and finite difference approximations has been adopted to simulate the fully nonlinear sloshing wave. Herein, the external excitations, including rotational oscillation, are built-in within the kinematic and dynamic free surface boundary conditions. The predictions from the present model are compared with those of Nakayama and Wazhizu due to regular wave excitation in the roll mode, whereas the results from the combined excitations were compared with the results of Chen and Chiang. The sloshing oscillation induced by different combination of tank motions has been subjected to frequency domain analysis. The results exhibited the occurrence of dominant peak at the natural frequencies of the system, irrespective of the excitation frequency for the rotational motion. There is nearly a twofold increase in the peak amplitude if sway and roll excitations are in phase. Sloshing amplitude decreases if the vertical and rotational excitations act together.