Karman Vortex Creation Using Cylinder for Flutter Energy Harvester Device.

Ahmed Atrah,Nordin Jamaludin,Mohd Mohd Nor,Mohd Ab-Rahman,Mohd Nuawi,Hanim Salleh

doi:10.3390/mi8070227

Ahmed Atrah, Nordin Jamaludin + Show 4 more

Open Access

https://doi.org/10.3390/mi8070227

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Abstract

This study presents the creation of a Karman vortex for a fluttering electromagnetic energy harvester device using a cylinder. The effects of two parameters, which are the diameter and the position of the cylinder, were investigated on the Karman vortex profile and the amplitude of the fluttering belt, respectively. A simulation was conducted to determine the effect of the creation of the Karman vortex, and an experiment was performed to identify influence of the position of the cylinder on the fluttering belt amplitude. The results demonstrated that vortex-induced vibration occurred at the frequency of the first natural mode for the belt at 3 cm and 10 cm for the diameter and position of the cylinder, respectively. Under such configuration, an electromagnetic energy harvester was attached and vibrated via the fluttering belt inside the turbulent boundary layers. This vibration provides a measured output voltage and can be used in wireless sensors.

Highlights

The three main techniques for transferring mechanical vibration energy to electric energy are electromagnetic, piezoelectric, and electrostatic techniques
The electromagnetic technique can be applied in many scales and produces relatively high power densities given a relatively high velocity between the magnet and coil [5], and smaller internal impedance and larger current output compared to the piezoelectric technique [6,7]
Recent research in energy harvesting by electromagnetic induction has focused primarily on harvesting energy from the mechanical vibration of structures, to which the harvester is attached using the broadband effects [12,13,14]. Some of these researches demonstrated a significant enhancement of the harvested power and the frequency bandwidth of a multimodal vibration energy harvester consisting of arrays of coupled levitated magnets [15,16] when the device is excited beyond its critical Duffing amplitude [17,18]; this is due to magnetic nonlinearity and modal interactions [19]

Summary

Introduction

The three main techniques for transferring mechanical vibration energy to electric energy are electromagnetic, piezoelectric, and electrostatic techniques. Voltage can be generated by an electromagnetic energy harvester device that is attached to a belt inside turbulent boundary layers [20] This output voltage is dependent on the design of the device inside the flow field. Fei et al [20] proposed a similar device where the mechanical vibrations are transformed into electrical power via an electromagnetic transducer These devices motivated the present study of the pre-flutter characteristics of a belt with high aspect ratio (i.e., a membrane strip) in low subsonic flows. The present study focused on investigating the influences of the diameter and position of a bluff body (cylinder) on the natural frequency and the amplitude and synchronization region of vortex-induced vibrations (VIV) of energy harvesters. The energy harvesting approach used the fluttering belt behind a cylinder through electromagnetic transduction. The power density P in the wind is related to the cube of the wind speed, which can be expressed

Tash:eoretical Background

Parametric Analysis for Vortex Creation

Experimental Results and Discussion