scholarly journals Optimal energy harvesting from vortex-induced vibrations of cables

2016 ◽  
Vol 472 (2195) ◽  
pp. 20160583 ◽  
Author(s):  
G. O. Antoine ◽  
E. de Langre ◽  
S. Michelin
Keyword(s):  
Energy Harvesting ◽  
Flow Velocity ◽  
Passive Control ◽  
Optimal Harvesting ◽  
Control Mechanisms ◽  
Wake Oscillator ◽  
Vortex Induced Vibrations ◽  
Harvesting Systems ◽  
Gradient Based ◽  
Flexible Cables

Vortex-induced vibrations (VIV) of flexible cables are an example of flow-induced vibrations that can act as energy harvesting systems by converting energy associated with the spontaneous cable motion into electricity. This work investigates the optimal positioning of the harvesting devices along the cable, using numerical simulations with a wake oscillator model to describe the unsteady flow forcing. Using classical gradient-based optimization, the optimal harvesting strategy is determined for the generic configuration of a flexible cable fixed at both ends, including the effect of flow forces and gravity on the cable’s geometry. The optimal strategy is found to consist systematically in a concentration of the harvesting devices at one of the cable’s ends, relying on deformation waves along the cable to carry the energy towards this harvesting site. Furthermore, we show that the performance of systems based on VIV of flexible cables is significantly more robust to flow velocity variations, in comparison with a rigid cylinder device. This results from two passive control mechanisms inherent to the cable geometry: (i) the adaptability to the flow velocity of the fundamental frequencies of cables through the flow-induced tension and (ii) the selection of successive vibration modes by the flow velocity for cables with gravity-induced tension.

scholarly journals Optimal Energy Harvesting From Vortex-Induced Vibrations of Cables

2016 ◽  
Author(s):  
Guillaume O. Antoine ◽  
Sébastien Michelin ◽  
Emmanuel de Langre
Keyword(s):  
Energy Harvesting ◽  
Equation Of Motion ◽  
Complex Geometries ◽  
Wake Oscillator ◽  
Flow Fluctuations ◽  
Rigid Rods ◽  
Vortex Induced Vibrations ◽  
Numerical Tools ◽  
Carry Over ◽  
Flexible Cables

We propose to use flexible cables instead of rigid rods in devices extracting energy from Vortex-Induced Vibrations (VIVs). We use a linear equation of motion for the structure coupled with a nonlinear wake oscillator and numerical tools to simulate the VIVs of hanging strings/cables. While extracting energy from the VIVs of a straight cable with a harvester attached to one of its ends is as efficient as extracting energy from the VIVs of rigid structures, we find that the former is much more robust to flow fluctuations than the latter. We finally show that those results carry over to more complex geometries (e.g. catenary).

Energy Harvesting by Vortex-Induced Vibrations in Slender Structures

2013 ◽  
Author(s):  
Clement Grouthier ◽  
Sebastien Michelin ◽  
Emmanuel de Langre
Keyword(s):  
Energy Harvesting ◽  
Bluff Body ◽  
Travelling Waves ◽  
Analytical Calculation ◽  
Good Tool ◽  
Strongly Coupled ◽  
Wake Oscillator ◽  
Vortex Induced Vibrations ◽  
Optimal Efficiency ◽  
Slender Structures

Vortex-induced vibrations (VIV) are self-sustained oscillations of an immerged bluff body strongly coupled with its fluctuating wake. In this paper, energy harvesting by VIV of slender structures is investigated using a wake-oscillator model. The generic case of an infinitely long tensioned cable with periodically distributed harvesters is first investigated. The linear stability analysis of the model is a good tool to understand the strong influence of the different harvesting parameters on the efficiency. As the achieved efficiency is rather high, VIV seem promising as a mechanism for energy harvesting. The more realistic case of a hanging string with a single energy harvesting device at its upper extremity is thus considered. The optimal efficiency is still rather high, travelling waves develop towards the harvester when parameters are in the efficient region of the parameter space, which is identified thanks to a forced analytical calculation.

Energy Harvesting Using Vortex-Induced Vibrations of a Hanging Cable

2014 ◽  
Author(s):  
Clément Grouthier ◽  
Sébastien Michelin ◽  
Yahya Modarres-Sadeghi ◽  
Emmanuel de Langre
Keyword(s):  
Energy Harvesting ◽  
Oscillator Model ◽  
Mode Shapes ◽  
Maximum Efficiency ◽  
Wake Oscillator Model ◽  
Wake Oscillator ◽  
Vortex Induced Vibrations ◽  
Parametric Studies ◽  
Self Similar ◽  
The Impact

Many technologies based on fluid-structure interaction mechanisms are being developed to harvest energy from geo-physical flows. The velocity of such flows is low, and so is their energy density. Large systems are therefore required to extract a significant amount of energy. The question of the efficiency of energy harvesting using VIV of cables is addressed in this paper, through the case of a hanging cable with a harvester at its upper extremity. An experimental analysis of the vortex-induced vibrations of a hanging cable with variable tension along its length is first presented. It is shown that standing waves develop and that the extracted mode shapes are self-similar. This self-similar behaviour of the spatial distribution of the vibrations along the hanging string is explained theoretically by performing a linear stability analysis of an adapted wake-oscillator model. The hanging cable is then combined with a localized harvester and its dynamics is measured. An appropriate reduced-order wake-oscillator model is also used to perform parametric studies of the impact of the harvesting parameters on the efficiency. An optimal set of parameters is identified and it is shown that the maximum efficiency is close to the value reached with an elastically-mounted rigid cylinder. The efficiency is found to be essentially driven by the occurrence of traveling wave vibrations.

Analysis of magneto rheological elastomers for energy harvesting systems

2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé
Keyword(s):  
Magnetic Field ◽  
Energy Harvesting ◽  
Shear Strain ◽  
Magnetic Induction ◽  
Magnetic Particles ◽  
Homogeneous Magnetic Field ◽  
Electrical Signal ◽  
Harvesting Systems ◽  
Dc Bias ◽  
Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

Multimodal pizza-shaped piezoelectric vibration-based energy harvesters

2021 ◽  
pp. 1045389X2110069
Author(s):  
Virgilio J Caetano ◽  
Marcelo A Savi
Keyword(s):  
Energy Harvesting ◽  
Frequency Spectrum ◽  
Optimization Procedure ◽  
Single Mode ◽  
Ambient Vibration ◽  
Vibration Source ◽  
Element Analysis ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Harvesting Systems

Energy harvesting from ambient vibration through piezoelectric devices has received a lot of attention in recent years from both academia and industry. One of the main challenges is to develop devices capable of adapting to diverse sources of environmental excitation, being able to efficiently operate over a broadband frequency spectrum. This work proposes a novel multimodal design of a piezoelectric energy harvesting system to harness energy from a wideband ambient vibration source. Circular-shaped and pizza-shaped designs are employed as candidates for the device, comparing their performance with classical beam-shaped devices. Finite element analysis is employed to model system dynamics using ANSYS Workbench. An optimization procedure is applied to the system aiming to seek a configuration that can extract energy from a broader frequency spectrum and maximize its output power. A comparative analysis with conventional energy harvesting systems is performed. Numerical simulations are carried out to investigate the harvester performances under harmonic and random excitations. Results show that the proposed multimodal harvester has potential to harness energy from broadband ambient vibration sources presenting performance advantages in comparison to conventional single-mode energy harvesters.

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