A global analysis of a coupled violent vertical sloshing problem using an SPH methodology

Abstract

A dynamical system involving the decaying test of a partially filled liquid tank is analyzed in the present paper. This analysis is relevant for the design of aircraft fuel tanks, where the wings' structural dynamics are influenced by the complexity and the violence of the internal flow generated when atmospheric turbulence or gust is encountered. The study of this kind of system is performed in order to understand the extra energy dissipation caused by the confined fluid, and the interacting force between the fluid and the tank resulting from the vertical sloshing. A complete non-dimensional analysis of the problem in terms of additional damping has been performed, and the dependency on the most relevant non-dimensional numbers has been monitored. A coupled numerical simulation where both the tank and the fluid are combined has been used to study the system, and their results are compared to previous experiments. A smoothed particle hydrodynamics model, extensively validated in the sloshing literature, is used to calculate the magnitude and frequency of the vertical force between the fluid and the tank. The extra dissipation of the tank's mechanical energy caused by the fluid action is quantified for a particular configuration with constant filling level and a wide range of non-dimensional numbers. The sensitivity of the extra damping to the variation of the non-dimensional numbers is evaluated, and the most relevant ones are compared to the equivalent experimental tests. Results show that the numerical tool developed is able to capture the different phenomena involved and can be used to determine the influence of the different phenomena happening in violent vertically excited flows.