Experimental and numerical analysis of energy dissipation in a sloshing absorber

The paper presents the results of an experimental-numerical study aimed at investigating the sloshing phenomenon in moving tuned sloshing dampers, with a particular attention to the physical mechanisms that determine the onset of hysteretic damping reducing the response of the substructure. Numerical simulations are carried out by a computational fluid dynamic model, while experiments are conducted by considering a rectangular tank having bottom dimensions of 40×20 cm, actuated by an electric torsional servomotor coupled with a ball screw transmission device. The case of harmonic displacements imposed to the tank is investigated, considering different amplitudes, frequencies and depths of the inner liquid. In order to determine the energy dissipation associated with the hysteretic force-displacement cycles, the sloshing force produced by the motion of the liquid is obtained by measuring the shear force between the tank and the moving base through a load cell. The numerical simulations demonstrate a fairly good agreement with the experimental results, both in terms of the kinematic response of the fluid and of the sloshing forces transmitted to the substructure. In particular, it is demonstrated that the computational fluid dynamic model allows an accurate estimation of the dissipated energy in different conditions, significantly outperforming the simplified analytical model often used in the design of tuned sloshing dampers.