scholarly journals Flutter instability in an internal flow energy harvester

2021 ◽  
Vol 915 ◽  
Author(s):  
Luis Phillipe Tosi ◽  
Benedikt Dorschner ◽  
Tim Colonius
Keyword(s):  
Energy Harvester ◽  
Internal Flow ◽  
Flow Energy ◽  
Flutter Instability

Abstract

An Experimental Investigation Into the Performance of a T-Shaped Piezoelectric Flow Energy Harvester

2013 ◽  
Author(s):  
P. B. Jain ◽  
M. R. Cacan ◽  
S. Leadenham ◽  
C. De Marqui ◽  
A. Erturk
Keyword(s):  
Geometric Parameter ◽  
Energy Harvester ◽  
Mechanical Response ◽  
Electrical Power ◽  
Response Spectra ◽  
Load Resistance ◽  
Flow Speed ◽  
Research Field ◽  
Flow Energy ◽  
Piezoelectric Cantilever

The harvesting of flow energy by exploiting aeroelastic and hydroelastic vibrations has received growing attention over the last few years. The goal in this research field is to generate low-power electricity from flow-induced vibrations of scalable structures involving a proper transduction mechanism for wireless applications ranging from manned/unmanned aerial vehicles to civil infrastructure systems located in high wind areas. The fundamental challenge is to enable geometrically small flow energy harvesters while keeping the cut-in speed (lowest flow speed that induces persistent oscillations) low. An effective design with reduced cut-in speed is known to be the T-shaped cantilever arrangement that consists of a horizontal piezoelectric cantilever with a perpendicular vertical beam attachment at the tip. The direction of incoming flow is parallel to the horizontal cantilever and perpendicular to the vertical and symmetric tip attachment. Vortex-induced vibration resulting from flow past the tip attachment is the source of the aeroelastic response. For a given width of the T-shaped harvester with fixed thickness parameters, an important geometric parameter is the length ratio of the tip attachment to the cantilever. In this paper we investigate the effect of this geometric parameter on the piezoaeroelastic response of a T-shaped flow energy harvester. A controlled desktop wind tunnel system is used to characterize the electrical and mechanical response characteristics for broad ranges of flow speed and electrical load resistance using different vertical tip attachment lengths for the same horizontal piezoelectric cantilever. The variations of the electrical power output and cut-in speed with changing head length are reported along with an investigation into the electroaeroelastic frequency response spectra.

scholarly journals Modeling the capacity of a novel flow-energy harvester

2009 ◽  
Vol 33 (5) ◽  
pp. 2207-2217 ◽  
Author(s):  
Qiang Zhu ◽  
Max Haase ◽  
Chin H. Wu
Keyword(s):  
Energy Harvester ◽  
Flow Energy

Flow Energy Harvesters With a Nonlinear Restoring Force

2014 ◽  
Author(s):  
Ali H. Alhadidi ◽  
Amin Bibo ◽  
Mohammed F. Daqaq
Keyword(s):  
Bluff Body ◽  
Energy Harvester ◽  
Restoring Force ◽  
Energy Harvesters ◽  
Flow Energy ◽  
Nonlinear Restoring Force ◽  
Aerodynamic Loading ◽  
Lumped Parameter ◽  
Piezoelectric Cantilever ◽  
Different Shapes

This ppppaper examines the performance of a galloping energy harvester possessing a nonlinear restoring force. To achieve this goal, a flow energy harvester consisting of a piezoelectric cantilever beam augmented with a square-sectioned bluff body at the free end is considered. Two magnets located near the tip of the bluff body are used to introduce the nonlinearity which strength and nature can be altered by changing the distance between the magnets. A lumped-parameter aero-electromechanical model adopting the quasi-steady assumption for aerodynamic loading is presented and utilized to numerically simulate the harvester’s response. Wind tunnel tests are also performed to validate the numerical simulations by conducting upward and downward wind velocity sweeps. Results comparing the relative performance of several harvesters with potential functions of different shapes demonstrate that a mono-stable potential function with a hardening restoring force can outperform all other configurations.

An Underwater Magnetically Coupled Bistable Vibration Energy Harvester Using Wings

2019 ◽  
Author(s):  
Hong-Xiang Zou ◽  
Ke-Xiang Wei ◽  
Lin-Chuan Zhao ◽  
Wen-Ming Zhang ◽  
Lei Zuo ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Water Flow ◽  
Energy Harvester ◽  
High Reliability ◽  
Average Power ◽  
Vibration Energy ◽  
Coupling Mechanism ◽  
Vibration Energy Harvester ◽  
Water Flow Velocity ◽  
Flow Energy

Abstract Piezoelectric flow energy harvesting can be a potential way to yield endless electrical energy for small mechanical systems and wireless sensors. We propose a novel magnetically coupled bistable vibration energy harvester using wings for the applications in the water environment. The water flow energy can be harvested through the induced vibration of wings. The flextensional transducer can be packaged conveniently by using non-contact magnetic coupling mechanism. The magnetic force is amplified by the flextensional structure and transferred to the piezoelectric layer, thereby achieving higher power density and better reliability. A prototype was fabricated and tested in a water flume, which attended a maximum power of about 400 μW and the average power of 55 μW at the water flow velocity of 4 m/s. No significant variation occurred to the performance of the harvester after five days of continuous operation in the water, which indicates that the magnetically coupled vibration energy harvesting method has high reliability in the underwater environment.

A miniaturized gas flow energy harvester using diamagnetically stabilized levitation

2020 ◽  
Vol 92 (1) ◽  
pp. 10903
Author(s):  
Kun Zhang ◽  
Qi Gong ◽  
Xia Li ◽  
Yufeng Su ◽  
Zhiyong Duan
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Energy Harvester ◽  
Incident Angle ◽  
Pyrolytic Graphite ◽  
Maximum Flow ◽  
Induced Voltage ◽  
Flow Energy ◽  
The Stability ◽  
Maximum Voltage

In this paper, a miniaturized energy harvester is presented to scavenge gas flow energy. A magnet rotor with three teeth evenly distributed on the edge was introduced into the energy harvester, and it is frictionlessly levitated between two highly oriented pyrolytic graphite (HOPG) sheets. The energy harvester is designed to operate at a single stable equilibrium, so as to improve the stability of the rotor. The optimal incident angle of the gas flow was determined to be 83°. On the basis of the optimal angle, two different configurations of the energy harvester were proposed. Configuration A includes one nozzle, while Configuration B has two centrosymmetric nozzles. The maximum flow rate that enables Configurations A to work stably is limited, which can be increased by thickening the magnet rotor. The maximum voltage of configuration A was 0.28 V at a flow rate of 1500 sccm for the 4.5 mm thick rotor. Configuration B can run stably at any flow rate bigger than 250 sccm and the induced voltage increases with the driving flow rate. At the flow rate of 3000 sccm, the energy harvester of Configuration B can generate a maximum voltage of 3 V and light up tens of light-emitting-diodes (LEDs).

A broadband flow energy harvester induced by the wake of a bluff body

2021 ◽  
Author(s):  
Wen-An Jiang ◽  
Xin-dong Ma ◽  
Yong Wang ◽  
Mao Liu ◽  
Li-qun Chen ◽  
...  
Keyword(s):  
Bluff Body ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Analytical Data ◽  
Degree Of Freedom ◽  
Nonlinear Flow ◽  
Physical Parameters ◽  
Restoring Force ◽  
Flow Energy ◽  
Two Degree Of Freedom

Abstract Wake galloping energy harvesting have been extensively developed to scavenge flow energy from vortex-induced oscillations. Hence, the wake-galloping harvester only has a natural frequency which leads to a very narrow bandwidth. Therefore, it does not operate well under the wide region of shedding frequencies in variable wind speed. To overcome the vital issue, this paper we explored a novel two-degree-of-freedom nonlinear flow energy harvester to collect flow energy induced by the wake of a bluff body. The nonlinear restoring force is realized by using a repulsive magnetic force between two cuboid-shaped permanent magnets, and the electromechanical coupling equations is presented. Based on the method of harmonic balance, the electromechanical governing equations is decoupled, and the first order harmonic solutions are implemented. The modulation equations are established, the amplitude-frequency figures of displacement and voltage are depicted with different detuning parameters. The superiority of the presented energy harvester is contrasted with the single-degree-of-freedom linear and nonlinear cases, the results revealed that the two-degree-of-freedom nonlinear scheme can enhance the bandwidth of flow energy capture. The effect of physical parameters on the scavenged power is discussed. The accuracy and efficiency of the approximate analytical data are examined by numerical simulations.

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