Techno Press
You logged in as Techno Press

Wind and Structures
  Volume 26, Number 2, February 2018, pages 57-68

Experimental study on wake-induced vibrations of two circular cylinders with two degrees of freedom
Xiaoqing Du, Benjian Jiang, Chin Dai, Guoyan Wang and Suren Chen

    Wind tunnel tests are conducted to investigate wake-induced vibrations of two circular cylinders with a center-to-center spacing of 4 diameters and attack angle varying from 0 to 20 for Reynolds numbers between 18,000 and 168,800. Effects of structural damping, Reynolds number, attack angle and reduced velocity on dynamic responses are examined. Results show that wake-induced vortex vibrations of the downstream cylinder occur in a wider range of the reduced velocity and have higher amplitudes in comparison to the vortex-induced vibration of a single circular cylinder. Two types of wake-induced instability phenomena with distinct dynamic characteristics are observed, which may be due to different generation mechanisms. For small attack angles like 5 and 10, the instability of the downstream cylinder characterizes a one-degree-of-freedom (1-DOF) oscillation moving in the across-wind direction. For a large attack angle like 20, the instability characterizes a two-degree-of-freedom (2-DOF) oscillation with elliptical trajectories. For an attack angle of 15, the instability can transform from the 1-DOF pattern to the 2-DOF one with the increase of the Reynolds number. Furthermore, the two instabilities show different sensitivity to the structural damping. The 1-DOF instability can be either completely suppressed or reduced to an unsteady oscillation, while the 2-DOF one is relatively less sensitive to the damping level. Reynolds number has important effects on the wake-induced instabilities.
Key Words
    two circular cylinders; wind tunnel test; wake-induced vibration; Reynolds number effect
Xiaoqing Du and Benjian Jiang: Department of Civil Engineering, Shanghai University, Shanghai, China
Chin Dai: Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai, China
Guoyan Wang: School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, China
Suren Chen: Department of Civil and Environmental Engineering, Colorado State University, Colorado, United States

Techno-Press: Publishers of international journals and conference proceedings.       Copyright © 2021 Techno Press
P.O. Box 33, Yuseong, Daejeon 305-600 Korea, Tel: +82-42-828-7996, Fax : +82-42-828-7997, Email: