A Numerical Investigation of Natural Characteristics of a Partially Filled Tank Using a Substructure Method

摘要

Sloshing of liquid in a partially filled tank has been a concern in a number of engineering fields, including automobile, aerospace and marine industries. This paper reports the findings of a numerical investigation into the variations of natural frequencies and mode shapes of a tank-liquid system. The effects of a few parameters of the system, such as the liquid filling level, geometry shape and wall stiffness of the tank, etc. on the natural vibrations, especially natural frequencies, are examined. Both spherical and rectangular tanks are studied. Fluid-structure interaction systems are described by a generalized linear fluid-structure interaction theory of which the structure is governed by the theory of linear elasticity and the fluid by a wave equation as well as various suitable boundary conditions, such free surface wave disturbance and kinematic and dynamic coupling conditions on the fluid-solid interfaces. Numerical simulations are based on a mixed finite element substructure - subdomain method and the corresponding computer code which adopts the displacement of solid and the pressure in the fluid as variables to model the coupling system.rnA spherical liquid container and a 2D cross section of LNG tank are simulated using the developed method. The results are compared with the available theoretical, reported numerical and experimental results to demonstrate the applications of the method. Some guidelines obtained by this investigation are presented which may be a reference for dynamic designs of liquid-container system considering fluid-solid interactions.