Experimental and numerical analysis of Tuned Sloshing Dampers and Liquid Column Vibration Absorbers for the vibration control of a multi storey frame using fluids of different viscosities

Tuned Liquid Dampers (TLDs) dissipate energy through the out-of-phase fluid motion inside a container relative to a structure. This study experimentally and numerically analyses the two main TLD configurations: Tuned Sloshing Dampers (TSDs) and Liquid Column Vibration Absorbers (LCVAs). Shake table tests are used to evaluate the Frequency Response Function of a four-story scaled frame with and without TSDs and LCVAs, comparing the effect of water and two commercially available non-organic fluids of diverse viscosities under different horizontal harmonic base excitation amplitudes. A numerical analysis supports the interpretation of the influence of key parameters - mass, damping and frequency of the device - and evaluates the precision of existing formulations found in the literature and codes. For TSDs, the experimentally measured and numerically defined mass and frequency agree with the literature. For LCVAs the existing mass participation prediction does not align with the results: only 25 % of the total fluid mass, corresponding to the fluid inside the columns, is effective. Additionally, a new LCVA frequency formulation is proposed, reducing prediction error from 15 to 2 %. The amplitude and viscosity-dependence of the damping ratio lead to defining different optimal fluid selections depending on the container: high viscosity fluids improve surface control and vibration suppression for TSDs, reducing both the response at resonance (99.5 %) and the maximum response (84 %). For LCVAs, higher viscosity causes excess damping and non-optimum performance. In this case water yields the best resonance reduction (98 %). These findings are aimed at refining the practical application of TLDs and improving their numerical definition.