Performance characteristics of a shake flashlight

The paper presents an analytical, numerical and experimental analysis of the special designed system for energy harvesting. The harvester system consists of two identical magnets rigidly mounted to the tube’s end. Between them, a third magnet is free to magnetically levitate (pseudo-levitate) due to the proper magnet polarity. The behaviour of the harvester is significantly complicated by a electromechanical coupling. It causes resonance curves to have a distorted shape and a new solution from which the recovered energy is higher is observed. The Harmonic Balance Method (HBM) is used to approximately describe the response and stability of the mechanical and electrical systems. The analytical results are verified by a numerical path following (continuation) method and experiment test with use of a shaker. The influence of harvester parameters on the system response and energy recovery near a main resonance is studied in detail.

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“…If the flashlights vigorously shaken back and forth, then a magnet to move through a coil causing charge to the battery [33].…”

Section: Magnetic Levitation Architecturesmentioning

confidence: 99%

Theoretical and Experimental Investigations of a Pseudo-Magnetic Levitation System for Energy Harvesting

Kęcik

Mitura

2020

Sensors

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“…7a, a shaped foam buoy with a mast topped by two magnets moving through a tube with four fixed coils, Fig. 7c, the latter parts coming out of two deconstructed shake or Faraday flashlights [22,25,39], Fig. 7b, with the buoy constrained to glide along a fixed, guiding mast.…”

Section: Novel Rogue-wave-energy Devicementioning

confidence: 99%

“…where we have added the effective circuit and coil resistances R i and R c and linearised (around I = 0 and usingZ ) model of the LED light, as well as a consistency equation, with (22) andn • ∇φ = 0 at the fixed, vertical walls. Note that from (23f),Ĩ = (P Q + γ G(Z )Z )/L i .…”

Section: Wave-to-wire Monolithic Wave-energy Modelmentioning

confidence: 99%

From Bore–Soliton–Splash to a New Wave-to-Wire Wave-Energy Model

Bokhove

Kalogirou

Zweers³

2019

Water Waves

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We explore extreme nonlinear water-wave amplification in a contraction or, analogously, wave amplification in crossing seas. The latter case can lead to extreme or rogue-wave formation at sea. First, amplification of a solitary-water-wave compound running into a contraction is disseminated experimentally in a wave tank. Maximum amplification in our bore-soliton-splash observed is circa tenfold. Subsequently, we summarise some nonlinear and numerical modelling approaches, validated for amplifying, contracting waves. These amplification phenomena observed have led us to develop a novel wave-energy device with wave amplification in a contraction used to enhance wave-activated buoy motion and magnetically induced energy generation. An experimental proof-of-principle shows that our wave-energy device works. Most importantly, we develop a novel wave-to-wire mathematical model of the combined wave hydrodynamics, wave-activated buoy motion and electric power generation by magnetic induction, from first principles, satisfying one grand variational principle in its conservative limit. Wave and buoy dynamics are coupled via a Lagrange multiplier, which boundary value at the waterline is in a subtle way solved explicitly by imposing incompressibility in a weak sense. Dissipative features, such as electrical wire resistance and nonlinear LED loads, are added a posteriori. New is also the intricate and compatible finite-element space-time discretisation of the linearised dynamics, guaranteeing numerical stability and the correct energy transfer between the three subsystems. Preliminary simulations of our simplified and linearised wave-energy model are encouraging and involve a first study of the resonant behaviour and parameter dependence of the device.

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“…8a), a shaped foam buoy with a mast topped by two magnets moving through a tube with four fixed coils, Fig. 8c), the latter parts coming out of two deconstructed shake or Faraday flashlights [20,25,38], Fig. 8b), with the buoy constrained to glide along a fixed, guiding mast.…”

Section: Novel Rogue-wave-energy Devicementioning

confidence: 99%

Untitled

2019

Preprint

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We explore extreme nonlinear water-wave amplification in a contraction or, analogously, wave amplification in crossing seas. The latter case can lead to extreme or rogue-wave formation at sea. First, amplification of a solitary-water-wave compound running into a contraction is disseminated experimentally, for small-scale and larger wavetanks. Maximum amplification in our bore-soliton-splash observed is circa tenfold. Subsequently, nonlinear and numerical modelling approaches are developed and validated for amplifying, contracting waves. Amplification phenomena observed have led us to develop a novel wave-energy device with wave amplification in a contraction used to enhance wave-buoy motion and magnetically-induced energy generation. An experimental proof-of-principle shows that our wave-energy device works. Furthermore, we develop a monolithic, mathematical model of wave hydrodynamics, buoy motion and electric power generation by magnetic induction, satisfying one grand variational principle in its conservative limit. Dissipative features, electrical wire resistance and nonlinear LED-loads, are added a posteriori. Preliminary simulations of our simplified (linear) wave-energy model are encouraging. Further highlights discussed are: exact modelling of crossing seas with Kadomtsev-Petviashvili's equation, bore-soliton-splash' relevance to devastating Tohoku tsunami run-up in 2011, nonlinear wave-energy optimisation and a steel-soliton-splash artwork. ‡

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Performance characteristics of a shake flashlight

Cited by 3 publications

References 5 publications

Theoretical and Experimental Investigations of a Pseudo-Magnetic Levitation System for Energy Harvesting

Theoretical and Experimental Investigations of a Pseudo-Magnetic Levitation System for Energy Harvesting

From Bore–Soliton–Splash to a New Wave-to-Wire Wave-Energy Model

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