Effect of Bottom Geometry on the Natural Sloshing Motion of Water inside Tanks: An Experimental Analysis

Antonio Agresta,Nicola Cavalagli,Filippo Ubertini,Chiara Biscarini

doi:10.3390/app11020605

Antonio Agresta, Nicola Cavalagli + Show 2 more

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https://doi.org/10.3390/app11020605

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Abstract

The present work aims at understanding and modelling some key aspects of the sloshing phenomenon, related to the motion of water inside a container and its effects on the substructure. In particular, the attention is focused on the effects of bottom shapes (flat, sloped and circular) and water depth ratio on the natural sloshing frequencies and damping properties of the inner fluid. To this aim, a series of experimental tests has been carried out on tanks characterised by different bottom shapes installed over a sliding table equipped with a shear load cell for the measurement of the dynamic base shear force. The results are useful for optimising the geometric characteristics of the tank and the fluid mass in order to obtain enhanced energy dissipation performances by exploiting fluid–structure interaction effects.

Highlights

The aim of this paper is to investigate the dynamic properties of the sloshing phenomenon inside rectangular tanks characterised by different bottom shapes
The power spectra were extracted from the dynamic records of the base shear force in order to estimate the natural angular frequency ωw, and the natural sloshing frequency fw, for the different liquid h/L ratios
The performed experimental campaign consisted of a series of tests on a tank filled with water at nine different depths and each case tested for three different bottom geometries, namely flat, sloped and circular

Summary

Introduction

The aim of this paper is to investigate the dynamic properties of the sloshing phenomenon inside rectangular tanks characterised by different bottom shapes. The interest is to investigate two particular aspects of the fluid–structure interaction, namely the natural sloshing frequency of the fluid inside the tank and its damping feature. The latter is related, among the other features, to the beating phenomenon [1], characterised by the undesired dynamic forces induced on the substructure due to sloshing motion. In the case of a container suspended as a bifilar pendulum, gravity directly provides the restoring force, working in concert with, or in opposition, to the hydrodynamic forces, so that both in-phase and antiphase oscillations can occur [14,15,16]. The sloshing liquid is expected to be out of phase with the oscillating tank, always accumulating in the direction opposite to that of the containers’ motion

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