Hydrokinetic Vortex Induced Vibration (VIV) Energy Harvester

2021 ◽  
Author(s):  
Xiaoyu Zhou ◽  
Vesselina Roussinova ◽  
Vesselin Stoilov
Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3101
Author(s):  
Xiaobiao Shan ◽  
Haigang Tian ◽  
Han Cao ◽  
Tao Xie

This paper proposes a novel and efficient energy harvester (EH) system, for capturing simultaneously flutter and vortex-induced vibration. There exists a coupling effect between flexible spring energy harvester (FSEH) and cantilever beam energy harvester (CBEH) in aerodynamic response and output characteristic. Many prototypes of the harvester were manufactured to explore the coupling effect in a wind tunnel. The experimental results demonstrate that FSEH is mainly subjected to flutter-induced vibration and CBEH undergoes vortex-induced vibration. Disturbance of FSEH first takes place, a limited oscillation cycle then occurs, and chaos ultimately happens as airflow velocity increase. Root mean square voltages are more than 11 V for FSEH at beyond 10.52 m/s, which shows the better output performance over the existing harvesters. Vibration response and output voltage of various harvesters are mutually enhanced with each other. An enhancing ratio for FSEH-130-25 is up to 69.6% over FSEH-130-0, while the enhancing ratio for CBEH-130-30 is 198.3% compared to CBEH-0-30. Field application testing manifests that discharging time to power the pedometer is almost twice as long as the charging one for FSEH-130-25 at 14.48 m/s. The current research offers a suggestive guidance for promoting future practical application in micro airfoil aircrafts.


Author(s):  
Farshad Moradi Gharghani ◽  
Mohamad Ali Bijarchi ◽  
Omid Mohammadi ◽  
Mohammad Behshad Shafii

Abstract Renewable energies could be a good solution to the problems associated with fossil fuels. The storage of wind energy by means of small-scale devices rather than large-scale turbines is a topic that has gained lots of interest. In this study, a compact device is proposed to harvest wind energy and transform it into electrical energy, by means of oscillations of a magnet into a coil, using the concept of vortex-induced vibration (VIV) behind a barrier. For a more comprehensive investigation, this system is studied from two viewpoints of fluid mechanics (without magnet) and power generation (with the magnet). For this purpose, an oscillating plate hinging on one side and three barriers with different geometrical shapes including cylindrical, triangular and rectangular barriers are used. In addition to the effect of barrier geometry, the impacts of various barriers dimensions, the distance between the plate and the barriers as well as inclination angle of the plate with respect to the horizon on the amplitude of oscillations and generated power are investigated. Results showed that in each case, there is a unique Reynolds number in which the frequency of vortex shedding equals to the frequency of plate oscillation and the output power from the energy harvester device is maximum. Besides, by increasing the barrier dimensions, the amplitude of oscillations increases up to three times, which leads to a higher generated power. Finally, by considering the studied parameters, the best conditions for generating energy using the VIV method are presented for design purposes. Among all the considered cases, the cylindrical barrier with the highest diameter and nearest distance to the plate led to the highest efficiency (0.21%) in comparison with other barriers.


2020 ◽  
Author(s):  
Xiaoyu Zhou ◽  
Vesselina Roussinova ◽  
Vesselin Stoilov

Abstract This paper investigates the performance of vortex-induced vibration (VIV) energy harvester in low-speed water flow. The proposed VIV harvester is extracting hydrokinetic energy from the flowing current and transferring it into mechanical vibrations. The vibrations are further converted into electrical energy using the piezoelectric transducer to supply the modern demand for energy-consumption. To meet the demand, the single harvester is analyzed to determine the suitable geometry for the bluff body that is sensitive to the low-speed flow. Furthermore, the converter must be able to harvest vibrations of varying amplitudes and frequencies. To maximize the power output, different array configurations of multiple bluff bodies are examined. A single positively buoyant elastically mounted cylinder is tested experimentally and at a low flow speed of 0.3 m/s, it can harvest vibrations with an average frequency of 1.8 Hz and peak to peak amplitude of 1.5d, where d is the diameter of the bluff body. It was found that for an array consisting of ten bluff bodies, the average frequency and peak to peak amplitude increases to 2.09Hz and 1.54d, respectively.


Energy ◽  
2021 ◽  
pp. 122933
Author(s):  
Xiaobiao Shan ◽  
Guangdong Sui ◽  
Haigang Tian ◽  
Zhaowei Min ◽  
Ju Feng ◽  
...  

2021 ◽  
Vol 585 (1) ◽  
pp. 128-138
Author(s):  
Jinpeng Meng ◽  
Xingwen Fu ◽  
Chongqiu Yang ◽  
Leian Zhang ◽  
Xianhai Yang ◽  
...  

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