Modal Analysis of Liquids in Rectangular Container

Abstract

The disturbance on the free surface of the liquid when the liquid-filled tanks are excited is called sloshing. It is important to know the fundamental natural frequencies of the system to analyze how a system vibrates under external excitations. The aim of the present paper is to perform find the natural sloshing frequencies of liquid filled containers experimentally and numerically. A swine sweep test is carried out on a shake table to find the slosh frequencies experimentally. Finite element technique is employed to solve slosh frequencies numerically. The governing equation of motion of the fluid is considered homogeneous, isotropic, inviscid and incompressible. The governing equations are expressed in terms of the pressure variable alone. The numerical natural frequencies of sloshing are calculated using 3D finite element model. The liquid domain is discretized using eight-node isoperimetric brick elements. Sloshing frequencies obtained from experiment and numerical model are in excellent agreement. The sloshing frequencies obtained are also compared with analytical solution available in literature and found to be in good agreement.