The Marquess of Worcester’s perpetual motion machine

Stewart, Maurice Bruce

doi:10.1119/1.2340677

Cited by 2 publications

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“…( 4). 17 A more recent case of large and unwanted oscillation of a bridge was the lateral swaying of the London Millennium Footbridge, after it opened in 2000. This was also a self-oscillation: as pedestrians attempt to walk straight along a swaying bridge, they move (relative to the bridge) against the sway, thus exerting a force on the bridge that is in phase The Strouhal frequency, at which a steady flow hitting a solid obstacle sheds turbulent vortices, will be discussed in Sec.…”

Section: Flow-induced Instabilitiesmentioning

confidence: 99%

“…happens, simply by geometry, to move with twice the frequency ω 0 in Eq. (17). The reason why parametric resonance for this system is most efficient when driven with angular frequency 2ω 0 is that the motor causes a negative damping of y(t), pulling up when the mass is going up and slackening when the mass is going down.…”

Section: G Parametric Resonancementioning

confidence: 99%

“…At the last moment he had attempted to rescue a black spaniel, Tubby, that had been left behind in the car when its owner fled on foot. The dog, terrified by the violent motion, merely bit Farquharson in the finger and later perished with the bridge[48] 17. In 1907, Rayleigh had reported a similar case of a tuning fork being driven at its resonant frequency by a steady cross-flow of air, even though the Strouhal frequency of vortex shedding by that flow did not match the fork's resonant frequency.…”

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confidence: 99%

“…Feynman jokes that "if you get an epitaph like that on your gravestone, you are doing fine." [9] 4 See[17] for an explanation of the non-operation of Worcester's wheel in terms of the explicit computation of the torques 5. The documentary A Machine to Die For: The Quest for Free Energy, released in 2003 and broadcast by Australian television[18], credulously showcases the work of various fringe researchers, while the few skeptics interviewed fail to adequately communicate any of the relevant physical concepts.…”

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confidence: 99%

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Self-oscillation

2013

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Physicists are very familiar with forced and parametric resonance, but usually not with self-oscillation, a property of certain dynamical systems that gives rise to a great variety of vibrations, both useful and destructive. In a self-oscillator, the driving force is controlled by the oscillation itself so that it acts in phase with the velocity, causing a negative damping that feeds energy into the vibration: no external rate needs to be adjusted to the resonant frequency. The famous collapse of the Tacoma Narrows bridge in 1940, often attributed by introductory physics texts to forced resonance, was actually a self-oscillation, as was the swaying of the London Millennium Footbridge in 2000. Clocks are self-oscillators, as are bowed and wind musical instruments. The heart is a "relaxation oscillator," i.e., a non-sinusoidal self-oscillator whose period is determined by sudden, nonlinear switching at thresholds. We review the general criterion that determines whether a linear system can self-oscillate. We then describe the limiting cycles of the simplest nonlinear self-oscillators, as well as the ability of two or more coupled self-oscillators to become spontaneously synchronized ("entrained"). We characterize the operation of motors as self-oscillation and prove a theorem about their limit efficiency, of which Carnot's theorem for heat engines appears as a special case. We briefly discuss how self-oscillation applies to servomechanisms, Cepheid variable stars, lasers, and the macroeconomic business cycle, among other applications. Our emphasis throughout is on the energetics of self-oscillation, often neglected by the literature on nonlinear dynamical systems.Comment: 68 pages, 33 figures. v4: Typos fixed and other minor adjustments. To appear in Physics Report

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Section: Flow-induced Instabilitiesmentioning

confidence: 99%

Section: G Parametric Resonancementioning

confidence: 99%

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confidence: 99%

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Self-oscillation

2013

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“…Whatever kinetic energy a mass gains as it falls will be entirely lost when it returns to its original height upon completing a revolution, regardless of the path taken. 38 Desaguliers conducted experimental demonstrations before the fellows of the Royal Society to support that conclusion. 39…”

Section: Orffyreus's Machinesmentioning

confidence: 94%

The mechanical career of Councillor Orffyreus, confidence man

Jenkins

2013

American Journal of Physics

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In the early 18th century, J. E. E. Bessler, known as Orffyreus, constructed several wheels that he claimed could keep turning forever, powered only by gravity. He never revealed the details of his invention, but he conducted demonstrations (with the machine's inner workings covered) that persuaded competent observers that he might have discovered the secret of perpetual motion. Among Bessler's defenders were Gottfried Leibniz, Johann Bernoulli, Professor Willem 's Gravesande of Leiden University (who wrote to Isaac Newton on the subject), and Prince Karl, ruler of the German state of Hesse-Kassel. We review Bessler's work, placing it within the context of the intellectual debates of the time about mechanical conservation laws and the (im)possibility of perpetual motion. We also mention Bessler's long career as a confidence man, the details of which were discussed in popular 19th-century German publications, but have remained unfamiliar to authors in other languages.Comment: 10 pages, 3 figures. v2: Expanded Sec. VI discussion of likely turning mechanism. More on Bessler's personal character in Sec. VIII. Changed format of notes and references. Minor points corrected or clarified, references improved. To appear in the American Journal of Physic

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The Marquess of Worcester’s perpetual motion machine

Cited by 2 publications

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Self-oscillation

Self-oscillation

The mechanical career of Councillor Orffyreus, confidence man

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