Energy harvesting by means of flow-induced vibrations on aerospace vehicles

Influence and optimization of the electrodes position in a piezoelectric energy harvesting flag

Flow-induced vibration of three unevenly spaced in-line cylinders in cross-flow

Energy harvesting from different aeroelastic instabilities of a square cylinder

The influence of fin-shaped rod (FSR) with different installation positions on wind-induced vibration and energy harvesting of a cylinder-based aeroelastic energy harvester are studied by experiments and simulations. Two FSRs are installed symmetrically on the surface of a circular cylinder, and the coverage angle of each FSR is 20°. The installation position of FSRs on the cylinder is represented by the placement angle, θ, which varies in the range of ±160°. And the tested wind speed range is 0–6.8 m s−1. The results show that FSRs change the position of the separation point of the boundary shear layers, further affect the formation and shedding of vortices. Then the force on the cylinder changes, which causes the energy harvester to produce different vibration responses and energy outputs. When 0° < θ < 70°, back-to-back vortex-induced vibration (VIV) and galloping can be observed for FSR-cylinder, and the output power increases with the increase of wind speed, the maximum output voltage and power reach 18.1 V and 1.645 mW. For 70° ⩽ θ < 120°, the vibration of FSR-cylinder is suppressed, which is not conducive for energy harvesting. When 120° < θ ⩽ 160°, the vibration of FSR-cylinder firstly experiences VIV and then galloping occurs after reaching the critical wind speed.

Effects of installation position of fin-shaped rods on wind-induced vibration and energy harvesting of aeroelastic energy converter

Any device aiming to harness the abundant clean and renewable energy from ocean and other water resources must have high energy density, be unobtrusive, have low maintenance, be robust, meet life cycle cost targets, and have a 10–20 year life. The vortex induced vibration aquatic clean energy (VIVACE) converter invented by Bernitsas and Raghavan, patent pending through the University of Michigan satisfies those criteria. It converts ocean/river current hydrokinetic energy to a usable form of energy such as electricity using VIV successfully and efficiently for the first time. VIVACE is based on the idea of maximizing rather than spoiling vortex shedding and exploiting rather than suppressing VIV. It introduces optimal damping for energy conversion while maintaining VIV over a broad range of vortex shedding synchronization. VIV occurs over very broad ranges of Reynolds (Re) number. Only three transition regions suppress VIV. Thus, even from currents as slow as 0.25 m/ s, VIVACE can extract energy with high power conversion ratio making ocean/river current energy a more accessible and economically viable resource. In this paper, the underlying concepts of the VIVACE converter are discussed. The designs of the physical model and laboratory prototype are presented.

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Shah Nitixaben Rajeshkumar

Papers

VIVACE (Vortex Induced Vibration Aquatic Clean Energy). A new concept in generation of clean and renewable energy from fluid flow