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| [[File:Actuator disk.svg|thumb|An actuator disk accelerating a fluid flow from right to left]]
| | 51 year old Medical Analytical Radiographer Archie Persaud from Bloomfield Ridge, spends time with pursuits like snow biking, new launch property singapore and snorkeling. that contains planing a trip to Archaeological Ruins at Moenjodaro.<br><br>Here is my homepage :: [http://eduplustutoring.com/questions/6-steps-to-creating-an-effective-sticky-word-enterprise-plan/ http://eduplustutoring.com/] |
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| In [[fluid dynamics]], the '''momentum theory''' or '''disk actuator theory''' is a theory describing a [[mathematical model]] of an ideal actuator disk, such as a [[propeller]] or [[helicopter]] [[helicopter rotor|rotor]], by [[William John Macquorn Rankine|W.J.M. Rankine]] (1865), [[Alfred George Greenhill]] (1888) and [[R.E. Froude]] (1889).
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| The rotor is modeled as an infinitely thin disc, inducing a constant velocity along the axis of rotation. The basic state of a helicopter is [[hover]]ing. This disc creates a flow around the rotor. Under certain mathematical premises of the fluid, there can be extracted a mathematical connection between power, radius of the rotor, [[torque]] and induced velocity. [[Friction]] is not included.
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| For a stationary rotor, such as a helicopter in hover, the power required to produce a given thrust is:
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| <math>P = \sqrt{\frac{T^3}{2 \rho A}}</math> | |
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| Where:
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| * T is the [[thrust]]
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| * <math>\rho</math> is the [[density of air]] (or other medium)
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| * A is the area of the rotor disc
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| A device which converts the translational energy of the fluid into rotational energy of the axis or vice versa is called a '''Rankine disk actuator'''. The real life implementations of such devices are e.g. marine and aviation [[propeller]]s, [[windmill]]s, [[helicopter rotor]]s, [[centrifugal pump]]s, [[wind turbine]]s, [[turbocharger]]s and [[agitator_(device)|chemical agitator]]s.
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| ==See also==
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| * [[Blade element theory]]
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| * [[Circulation (fluid dynamics)]]
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| * [[Disk loading]]
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| * [[Kutta-Joukowski Circulation]]
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| ==External links==
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| {{Commons|Category:Actuator disk theory|Actuator disk theory}}
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| * [http://www.public.iastate.edu/~aero442/unit2.pdf Momentum theory (Froude)]
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| [[Category:Fluid dynamics]]
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51 year old Medical Analytical Radiographer Archie Persaud from Bloomfield Ridge, spends time with pursuits like snow biking, new launch property singapore and snorkeling. that contains planing a trip to Archaeological Ruins at Moenjodaro.
Here is my homepage :: http://eduplustutoring.com/