Effect of incoming gravity waves on the energy extraction efficiency of flapping wing hydroelectric generators

2022 ◽  
Vol 245 ◽  
pp. 110590
Author(s):  
Bing Zhu ◽  
Zhiwei Tai ◽  
Dongmei Du ◽  
Junwei Zhang
2021 ◽  
Vol 228 ◽  
pp. 108901
Author(s):  
Xiao-Dong Bai ◽  
Ji-Sheng Zhang ◽  
Jin-Hai Zheng ◽  
Yong Wang

2011 ◽  
Vol 23 (4) ◽  
pp. 885-889
Author(s):  
陈星 Chen Xing ◽  
刘文广 Liu Wenguang ◽  
姜宗福 Jiang Zongfu ◽  
靳冬欢 Jin Donghuan

2019 ◽  
Vol 13 (11) ◽  
pp. 1823-1832 ◽  
Author(s):  
Bing Zhu ◽  
Wei Zhang ◽  
Yun Huang

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 700 ◽  
Author(s):  
Philipp Dorsch ◽  
Toni Bartsch ◽  
Florian Hubert ◽  
Heinrich Milosiu ◽  
Stefan J. Rupitsch

We present a two-stage energy extraction circuit for a piezoelectric energy harvester, powering an asset-tracking system. Exploiting non-sinusoidal accelerations generated by many logistic transport devices, e.g., pushcarts, forklifts, assembly belts or cars, we are able to harvest sufficient electrical energy to transmit radio signals, which will allow to track the object when it is moving. By using the proposed energy extraction circuit, the energy extraction efficiency could be improved by at least 30% compared to a single-stage solution for sinusoidal excitations. In the practical use-case, the two-stage energy extraction network performs more than four times better compared to the single staged on.


2019 ◽  
Vol 11 (2) ◽  
pp. 023302 ◽  
Author(s):  
Bing Zhu ◽  
Peng Xia ◽  
Yun Huang ◽  
Wei Zhang

1986 ◽  
Vol 119 ◽  
pp. 395-398
Author(s):  
Sanjay M. Wagh ◽  
N. Dadhich

Using the fact that the efficiency of the revived (Wagh et al 1985) Penrose process of energy extraction from black holes immersed in electromagnetic fields can be very high (Parthasarathy et al, 1986) we show that this process can comfortably power the ‘central engine’ in Active Galactic Nuclei. The microphysical Penrose process energized particles will be ultrarelativistic in the asymptotic frame. Hence the kinematical analysis of escaping photons by Piran and Shaham (1977) will be a good approximation to the kinematics of these particles. From this analysis one expects the energized particles to emerge within an angle∼ 40° above and below the equatorial plane. These energetic particles, which are collimated in the funnel of an accretion disk and further on by the magnetic field, then, form supersonic, relativistic, bilateral jets. The relativistic Y factor for such jets can be expected to be ∼ 2 since these ultrarelativistic particles will effectively mimick radiation in ‘dragging’ the matter already injected inside the funnel. Various implications of high energy extraction efficiency are illustrated.


2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Fangrui Shi ◽  
Xiaojing Sun

Abstract Oscillating motion, an effective way to harvest energy, has gradually become a hotspot in bionic motion research in recent years. Means of improving the energy-extraction efficiency of a flapping foil harvester have long been a focus of researchers. This paper proposes a new flapping foil harvester with circulation control and explores the effects of different parameters on its energy-extraction capacity to improve efficiency and achieve lowest cost. Setting the injection ports on the upper and lower surfaces near the trailing edge of the foil and implementing injection control during motion, the effects of the location of the injection port, pitching amplitude, momentum coefficient, reduced frequency, and jet mode on the circulation control flapping foil are systematically investigated under the condition of a Reynolds number of 13,800. The results show that circulation control can enhance the energy-extraction efficiency of a flapping foil across a wide range of parameters, in which the location of the injection port and momentum coefficient have the most obvious influence on efficiency, followed by pitching amplitude and reduced frequency. In addition, the jet mode is a crucial factor affecting net efficiency. Relative to the constant mode, the triangular mode of circulation control has the lowest energy consumption, and the net energy-extraction efficiency reaches up to 38.77% under a reduced frequency of 0.12, which is 22.24% higher than that of the plain flapping foil.


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