A Contribution to the Theory of Propulsion and the Screw Propeller

Lanchester, F. W.

doi:10.1111/j.1559-3584.1915.tb00408.x

Cited by 76 publications

(65 citation statements)

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“…From 1910 to 1915 there was a lively discussion on both Froude's and Parsons' theories between professors Henderson, Froude, Parsons and Lanchester in the pages of the popular English publication "Transactions of the Institute of Naval Architects" (see issues of 52, 53, 55 and 56). The author of the last article was Lanchester [28]. In the introduction to this article, he wrote: -"The present investigation takes for its starting point the simplified or idealized conception of propeller due to Mr. R.E.…”

Section: The Creation Of the Actuator Disc Theorymentioning

confidence: 99%

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Rotor theories by Professor Joukowsky: Momentum theories

Kuik

Sørensen

Okulov

2015

Progress in Aerospace Sciences

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Section: The Creation Of the Actuator Disc Theorymentioning

confidence: 99%

“…3 which was reproduced from Fig. 6 of [28] where Q is a measure (ratio) of the ideal work done by the force field and the energy in the wake, which according to Lanchester may not be equal).…”

Section: The Creation Of the Actuator Disc Theorymentioning

confidence: 99%

Rotor theories by Professor Joukowsky: Momentum theories

Kuik

Sørensen

Okulov

2015

Progress in Aerospace Sciences

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“…The linear momentum actuator disc theory often referred to as momentum theory or actuator disc theory was first introduced by Rankine [14] and Froude [15] to model ship propellers and subsequently extended by Lanchester [33] and Betz [34], who derived limits on the efficiency for this model. More recently, the theory has been particularised to model helicopter rotors [35], centrifugal pumps, turbochargers and wind turbines [36].…”

Section: Turbine Modellingmentioning

confidence: 99%

Sensitivity Analysis to Control the Far-Wake Unsteadiness Behind Turbines

2017

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Abstract:We explore the stability of wakes arising from 2D flow actuators based on linear momentum actuator disc theory. We use stability and sensitivity analysis (using adjoints) to show that the wake stability is controlled by the Reynolds number and the thrust force (or flow resistance) applied through the turbine. First, we report that decreasing the thrust force has a comparable stabilising effect to a decrease in Reynolds numbers (based on the turbine diameter). Second, a discrete sensitivity analysis identifies two regions for suitable placement of flow control forcing, one close to the turbines and one far downstream. Third, we show that adding a localised control force, in the regions identified by the sensitivity analysis, stabilises the wake. Particularly, locating the control forcing close to the turbines results in an enhanced stabilisation such that the wake remains steady for significantly higher Reynolds numbers or turbine thrusts. The analysis of the controlled flow fields confirms that modifying the velocity gradient close to the turbine is more efficient to stabilise the wake than controlling the wake far downstream. The analysis is performed for the first flow bifurcation (at low Reynolds numbers) which serves as a foundation of the stabilization technique but the control strategy is tested at higher Reynolds numbers in the final section of the paper, showing enhanced stability for a turbulent flow case.

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“…This is a basic principle that is easy to visualize: The complete extraction of kinetic energy from the flow would reduce the current speed to zero, thus leaving motionless water on the downstream side of the blade circle, which would prevent further flow through the turbine. The theoretical maximum fraction of kinetic energy flowing through a blade circle that can be extracted by the rotor is 59%-the well-known Lanchester-Betz limit, commonly referred to as the Betz limit (Lanchester 1915, Betz 1920, Van Kuik 2007. A real turbine will extract an even smaller fraction than this because of friction, turbulence, wake generation, possible cavitation, vibration of the rotor/generator assembly, and so on.…”

Section: Extracting Marine Hydrokinetic Energymentioning

confidence: 99%

Marine Hydrokinetic Energy from Western Boundary Currents

Bane

Muglia

et al. 2017

Annu. Rev. Mar. Sci.

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The kinetic energy in ocean currents, or marine hydrokinetic (MHK) energy, is a renewable energy resource that can help meet global energy requirements. An ocean circulation model-based census shows that subtropical surface western boundary currents (WBCs) are the only nearshore, large-scale currents swift enough to drive large electricity-generating ocean turbines envisioned for future use. We review several WBCs in the context of kinetic energy extraction. The power density in the Gulf Stream off North Carolina at times reaches several thousand watts per square meter at 75 m below the surface, and the annual average power is approximately 500-1,000 W m −2 . Significant fluctuations occur with periods of 3-20 days (Gulf Stream meanders) and weeks to months (Gulf Stream path shifts). Interannual variations in annual average power occur because of year-to-year changes in these WBC motions. No large-scale turbines presently exist, and the road to establishing MHK facilities in WBCs will encounter challenges that are similar in many aspects to those associated with the development of offshore wind power.

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A Contribution to the Theory of Propulsion and the Screw Propeller

Cited by 76 publications

References 0 publications

Rotor theories by Professor Joukowsky: Momentum theories

Rotor theories by Professor Joukowsky: Momentum theories

Sensitivity Analysis to Control the Far-Wake Unsteadiness Behind Turbines

Marine Hydrokinetic Energy from Western Boundary Currents

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