PowerFromActuatorDisk:

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   Compute power and power coefficient using actuator disk theory.
   This provides a limit on how much power a wind turbine can produce.
   "a" is defined from the relationship v3 = v0*(1 - 2*a) where v0 is the 
   wind speed in front of the machine and v3 is the wind speed at the end
   of the wake. Note that v3 = 0 is NOT the optimum value. The optimum
   value is with a = 1/3 so cP = 16/27. This can never be achieved in 
   practice due to aerodynamic losses.

   The rotor swept area is pi*r^2 for a HAWT and hd for a VAWT.

   Type PowerFromActuatorDisk for a demo.

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   Form:
   [p, cP] = PowerFromActuatorDisk( rho, A, v0, a )
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   Inputs
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   rho                 (1,1)  Atmospheric density (kg/m^3)
   A                   (1,1)  Rotor swept area (m^2)
   v0                  (1,:)  Wind velocity (m/s)
   a                   (1,1)  See above

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   Outputs
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   p                   (1,:)  Power (W)
   cP                  (1,:)  Power coefficient 

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   Reference: Wortman, A. J., "Introduction to Wind Turbine Engineering,"
              Butterworth Publishers, 1983, pp. 3-4.
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Children:

Common: Graphics/Plot2D