Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
Amplitude and frequency responses of a two-degree-of-freedom cylinder applied to fluid flow
Submission Author:
Matheus Rover Barbieri , SC
Co-Authors:
Matheus Rover Barbieri, Jonathan Utzig, Henry França Meier
Presenter: Matheus Rover Barbieri
doi://10.26678/ABCM.COBEM2019.COB2019-0752
Abstract
The study of the crossflow over bluff bodies has received special attention throughout the years, motivated by the occurrence of noise and damage in industrial applications. The presence of a cylinder modifies the flow around it, so that depending on flow velocity, vortex streets are formed downstream the tube. The motion amplitude and oscillation frequency are associated with these vortices patterns, in a way that the cylinder response depends on some factors such as the mass of the oscillating system and Reynolds number. An experimental methodology was proposed to investigate flow-induced vibrations, where a cylinder with a mass ratio equal to 13.66 was subject to crossflow with water as working fluid. The tube was suspended by four springs on a structure over the experimental facility, allowing it to oscillate with two degrees of freedom. Acceleration data were acquired in order to obtain motion amplitude and vibration frequency responses. The oscillation performance of the cylinder constituted an initial excitation branch and an upper branch, due to the applied velocity range, with amplitudes up to 1.3 diameters. The vibration frequency showed a dominant peak obtained through Fast Fourier Transform close to the natural frequency, resulting in a reduced frequency close to unity.
Keywords
Flow-induced Vibrations, Degrees of freedom, fluid-structure interaction (FSI), Accelerometry
