The influence of flexible fluid structure interactions on sway induced tank sloshing dynamics
Reza Saghi, Spyros Hirdaris, Hassan Saghi
Abstract
The analysis of liquid sloshing remains a challenging computational mechanics topic due to its complex underlying physics. The rapid simulation of sloshing problems requires accurate modelling of two-phase fluid dynamics and sloshing impacts on solid tank boundaries by suitable Flexible Fluid Structure Interaction (FFSI) models. This paper presents a hydroelastic model for the prediction of sway induced sloshing loads on flexible trapezoidal and rectangular tanks. Tank walls and a vertical baffle in way of the mid span of the tank bottom are idealized by Timoshenko beam structural dynamics. Hydroelastic analysis is enabled by a Boundary Element Method (BEM) that couples tank wall and baffle structural dynamics with free surface hydrodynamics to evaluate excitation forces and peak hydrodynamic pressures in way of the tank perimeter. Results show that for the case study presented accounting for the influence of hydroelasticity in a rectangular tank may lead to decrease of free surface oscillations and peak pressure by 20%. This is because the dynamics of tank flexibility are coupled with the angular frequency of the sway motion. These benefits amplify further for the case of trapezoidal tank designs for which the free surface and pressure of the trapezoidal tank with lateral angle θ=80° are decreased relative to the rectangular one by about 80% and 65%, respectively.