Active control of flow-induced vibrations of a flexible cylinder using direct velocity feedback

doi:10.1016/0022-460X(91)90521-K

Journal of Sound and Vibration

Volume 146, Issue 1, 8 April 1991, Pages 33-45

https://doi.org/10.1016/0022-460X(91)90521-K Get rights and content

Abstract

The use of a direct velocity feedback controller to attenuate actively vortex-induced vibrations of a flexible circular cylinder is described. The controller relies on its operation on an electromagnetic actuator, placed at a critical location inside the cylinder, to generate the control action necessary to resist the flow-induced excitations. The actuator is powered by a signal proportional and opposite to the velocity of the cylinder in order to enhance the overall viscous damping characteristics of the cylinder-actuator system. A prototype of the system was built, with a 3·175 cm diameter cylinder 26 cm long which has a first resonant frequency of 57·5 Hz. The system was tested in a wind tunnel, over a range of Reynolds number between 17 160 and 26 555, to demonstrate the feasibility of the controller in damping out the vortex-induced vibrations. The effect of varying the controller gain and the flow velocity on the system performance was determined in the frequency domain. The results obtained indicate that attenuations in excess of 80% are attained at resonant conditions. The experimental results are compared with the theoretical predictions obtained from a wake oscillator model the lift coefficients of which satisfy a modified van der Pol equation. Adequate agreement is found between theory and experiments.

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Active control of flow-induced vibrations of a flexible cylinder using direct velocity feedback

Abstract

Journal of Wind Engineering and Industrial Aerodynamics

Journal of Sound and Vibration

Journal of Sound and Vibration

Flow-induced Vibration

Vortex-induced oscillations

American Society of Mechanical Engineers Transactions, Journal of Applied

Preventing wind-induced oscillation of structures of circular sections