Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Comparing Analytical and Numerical Solutions for Fluid-Structure Problems with Free Surface Conditions: A Study on Tuned Liquid Dampers and Tuned Liquid Column Dampers
Submission Author:
Pedro Viégas , DF
Co-Authors:
Pedro Viégas, Marcus Vinicius Girão de Morais, Agnaldo Antonio, Raul Dari Durand Farfan
Presenter: Pedro Viégas
doi://10.26678/ABCM.COBEM2023.COB2023-0791
Abstract
Free surface problems can be used as Tuned Liquid Dampers (TLD) and Tuned Liquid Column Dampers (TLCD) to absorb free vibration in tall and slender structures like wind turbines and towers. These passive devices are characterized as fluid-structure problems. TLCDs were first proposed in tall buildings by Sakai et al. (1989). In the literature, this passive device is attractive for wind turbines due to its relatively low cost and good efficiency at low frequencies (Colwell and Basu, 2009). Yalla and Kareem (2000) proposed an approximate optimized solution for the TLCD head loss gain for a white noise spectrum. Alkmin, Fabro, and Morais (2018) optimized linearized TLCD parameters for a classic wind spectrum. Martins Morais and Avila (2019) experimentally showed the reduction of vibration of a TLCD in a reduced linear structure. There is also a small difference between theoretical frequencies and experimental results (2018). This study aims to compare analytical and numerical solutions of fluid-structure problems with free surface conditions, such as Tuned Liquid Damper (TLD) and Tuned Liquid Column Damper (TLCD). A Matlab program was implemented with a finite element nonsymmetric U-P formulation described by Newton-Zienkiewicz (1969). Three problems were presented: (a) a rectangular water tank, (b) a U-shaped tube filled with a liquid and (c) a multiple column damper. Using a forced harmonic excitation, the natural frequency of the first case was compared to the Graham and Rodriguez model, which uses mass-spring to represent the fundamental modes of motion. For the second case, the numerical fundamental frequencies of the U-shaped tube were compared to analytical solutions presented in several books of mechanical vibration.
Keywords
Sloshing, TLCD, Structural Vibration, fluid-structure interaction (FSI), Acoustic Finite Element Modelling
