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Wind and Structures
  Volume 34, Number 1, January 2022 (Special Issue) pages 73-80
DOI: https://doi.org/10.12989/was.2022.34.1.073
 


Experimental investigation of amplitude-dependent self-excited aerodynamic forces on a 5:1 rectangular cylinder
Qi Wang, Bo Wu, Hai-li Liao and Hanyu Mei

 
Abstract
    This paper presents a study on amplitude-dependent self-excited aerodynamic forces of a 5:1 rectangular cylinder through free vibration wind tunnel test. The sectional model was spring-supported in a single degree of freedom (SDOF) in torsion, and it is found that the amplitude of the free vibration cylinder model was not divergent in the post-flutter stage and was instead of various stable amplitudes varying with the wind speed. The amplitude-dependent aerodynamic damping is determined using Hilbert Transform of response time histories at different wind speeds in a smooth flow. An approach is proposed to extract aerodynamic derivatives as nonlinear functions of the amplitude of torsional motion at various reduced wind speeds. The results show that the magnitude of A2*, which is related to the negative aerodynamic damping, increases with increasing wind speed but decreases with vibration amplitude, and the magnitude of A3* also increases with increasing wind speed but keeps stable with the changing amplitude. The amplitude-dependent aerodynamic derivatives derived from the tests can also be used to estimate the post-flutter response of 5:1 rectangular cylinders with different dynamic parameters via traditional flutter analysis.
 
Key Words
    5:1 rectangular cylinder; aerodynamic derivatives; amplitude-dependence; post-flutter response; wind tunnel test
 
Address
Qi Wang: Department of Bridge Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, China

Bo Wu: Wind Engineering Key Laboratory of Sichuan Province, Chengdu, Sichuan, 610031, China

Hai-li Liao: Wind Engineering Key Laboratory of Sichuan Province, Chengdu, Sichuan, 610031, China

Hanyu Mei: Wind Engineering Key Laboratory of Sichuan Province, Chengdu, Sichuan, 610031, China
 

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