Computational study of sloshing behavior in 3-D rectangular tank with and without baffle under Seismic Excitation

Abstract

In this present study, sloshing behaviour in a 3-D rectangular tank is investigated using ANSYS-FLUENT (Version 13.0) software, subjected to various seismic excitation frequencies, different fill levels in tanks, with and without baffles conditions for altered baffle heights. For simulation of two-phase flow in a 3-D tank equipped with baffles, partially filled with incompressible, viscous fluid, volume of fluid (VOF) method based on the finite volume method (FVM) has been used. External Seismic excitations to the tank are imposed by Momentum Source input in cell zone conditions using User defined Function (UDF). Simulation is being carried out for 20 sec by using variable time method. The purpose of the present work is to examine computationally the effect of earthquake frequency content on the seismic behaviour of rectangular water storage tank system and to check variation of baffle height relative to the initial liquid fill level, affects the sloshing phenomenon, when the tank with vertical baffle at the center of the bottom wall, seismically excited with frequency equal to natural frequency of the liquid in the tank. The analysis shows that if the tank is subjected to Seismic excitations at resonant excitation Frequencies, liquid sloshing will become extreme and wall forces will be intensified. Result shows that after a certain height (critical height) of baffle, the liquid does not reach at roof top and when baffle height is equal to liquid fill level, almost linear behavior of the free surface is observed in each section. Time variation of pressure in relation to the baffle height is also investigated by monitoring at certain point in tank wall