Proceedings ArticleDOI
Force-Feedback Control in VIV Experiments
Øyvind N. Smogeli,Franz S. Hover,Michael S. Triantafyllou +2 more
- pp 685-695
TLDR
In this paper, a force-feedback control system for VIV experiments is designed and evaluated for the purpose of achieving high accuracy free vibration tests, and specific methods for minimizing the combined effect of mass and damping using control system fundamentals are described.Abstract:
A force-feedback control system for VIV experiments is designed and evaluated for the purpose of achieving high accuracy free vibration tests. Through an organized approach, this work details specific methods for minimizing the combined effect of mass and damping using control system fundamentals. The dynamics of the closed-loop system are analyzed, a numerical model constructed and a control scheme is chosen and implemented in real-time. The control system performance is evaluated by performing frequency response tests in air. Free vibrations of a smooth aluminum cylinder are performed at Reynolds number 19000. Test series with damping ratios of one, two and five percent are performed, all with nondimensional mass four. A peak amplitude ratio of 1.15 is observed for the case of lowest damping. Forced vibration tests with the same setup are performed and compared to the free vibration results, giving consistent results.Copyright © 2003 by ASMEread more
Citations
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Journal ArticleDOI
Defining the ‘modified Griffin plot’ in vortex-induced vibration: revealing the effect of Reynolds number using controlled damping
TL;DR: In this paper, the authors study the transverse vortex-induced vibrations of an elastically mounted rigid cylinder in a fluid flow and employ a technique to accurately control the structural damping, enabling the system to take on both negative and positive damping.
Journal ArticleDOI
Effect of mass-ratio, damping, and stiffness on optimal hydrokinetic energy conversion of a single, rough cylinder in flow induced motions
TL;DR: In this article, the second generation of virtual spring-damping system Vck, recently developed in the Marine Renewable Energy Laboratory (MRELab), enables embedded computer-controlled change of viscous-Damping and spring-stiffness for fast and precise oscillator modeling.
Journal ArticleDOI
An experimental investigation of vortex-induced vibration with nonlinear restoring forces
TL;DR: In this paper, the amplitude of a bluff body undergoing vortex-induced vibration (VIV) supported by linear and various nonlinear structural forces is examined, and the potential of nonlinear springs to aid in a VIV-based energy harvesting device is examined.
Journal ArticleDOI
Hydrokinetic energy conversion by two rough tandem-cylinders in flow induced motions: Effect of spacing and stiffness
Hai Sun,Hai Sun,Chunhui Ma,Eun Soo Kim,Eun Soo Kim,Gary Nowakowski,Erik Mauer,Michael M. Bernitsas +7 more
TL;DR: In this article, two cylinders are used in tandem with center-to-center spacing of 1.57, 2.0 and 2.57 diameters, harnessing damping ratio 0.00.
Journal ArticleDOI
Virtual spring-damping system for flow-induced motion experiments
TL;DR: In this article, the second generation of Vck is developed and validated by comparison of the FIM experiments between a Vck emulated oscillator and an oscillator with physical springs and dampers.
References
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Book
Flow-Induced Vibration
R. D. Blevins,H. Saunders +1 more
TL;DR: In this paper, the authors focus on applications for offshore platforms and piping; wind-induced vibration of buildings, bridges, and towers; and acoustic and mechanical vibration of heat exchangers, power lines, and process ducting.
Book ChapterDOI
Computer Controlled Systems
TL;DR: The degree of success of a computer control application depends mainly on the effectiveness of the algorithm, which is generally designed from plant specifications and desired performance characteristics.
Journal ArticleDOI
Vortex formation in the wake of an oscillating cylinder
TL;DR: In this paper, it was shown that the acceleration of the cylinder each half cycle induces the roll-up of the two shear layers close to the body, and thereby the formation of four regions of vorticity each cycle.
Journal ArticleDOI
Vortex shedding from oscillating bluff bodies
TL;DR: In this paper, the authors present a comprehensive review of vortex shedding in two-dimensional bluff-body wakes and present irrespective of whether the separating boundary layers are laminar or turbulent, and if the body is flexible this can cause oscillations.