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This study examines output energy and efficiency of a torsional flutter harvester in gusty winds. The proposed apparatus exploits the torsional flutter of a rigid flapping foil, able to rotate about a pivot axis located in the proximity of the windward side. The apparatus operates at the “meso-scale”; i.e., the apparatus’ projected area is equal to a few square meters. It has unique properties in comparison with most harvesting devices and small wind turbines. The reference geometric chord length of the flapping foil is about one meter. Energy conversion is achieved by an adaptable linkage connected to a permanent magnet that produces eddy currents in a multi-loop winding coil. Operational conditions and the post-critical flutter regime are investigated by numerical simulations. Several configurations are examined to determine the output power and to study the effects of stationary turbulent flows on the energy-conversion efficiency. This paper is a continuation of recent studies. The goal is to examine the operational conditions of the apparatus for a potentially wide range of applications and moderate mean wind speeds.
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This content will become publicly available on April 1, 2026
Exploiting Stochastic Resonance Principles to Influence the Efficiency of a Torsional-Flutter Energy Harvester in Turbulent Winds
Abstract Wind energy harvesters are emerging as a viable alternative to standard, large horizontal-axis wind turbines. This study continues a recent investigation on the operational features of a torsional-flutter-based apparatus, proposed by the author to extract wind energy. The apparatus is composed of a non-deformable, flapping blade-airfoil. A nonlinear torsional spring mechanism, either simulated by a Duffing model or a hybrid Duffing–van der Pol model, installed at equally spaced supports, enables limit-cycle, post-critical vibration. To enhance the output power, stochastic resonance principles are invoked through a novel, negative stiffness mechanism that is coupled to the eddy current device for energy conversion. The output power is explored by numerically solving the stochastic differential equation of the model, accounting for incoming flow turbulence. Three main harvester types with variable configuration are examined; the chord length of the blade-airfoil, used for energy harvesting, varies between 0.5 and 1 m; the spanwise-length-to-chord aspect ratio is four. The flapping frequency varies between 0.10 and 0.25 Hz. The study demonstrates that exploitation of negative stiffness mechanism can improve the performance of the harvester.
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- Award ID(s):
- 2020063
- PAR ID:
- 10635895
- Publisher / Repository:
- ASME
- Date Published:
- Journal Name:
- ASME Letters in Dynamic Systems and Control
- Volume:
- 5
- Issue:
- 2
- ISSN:
- 2689-6117
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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