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Old 27th Oct 2012, 10:31
  #205 (permalink)  
HazelNuts39
 
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OG;

Yes, if one arbitrarily assumes ...
that all the mass captured in the "virtual scoop" uniformly gets a downwash velocity vv, the power required for this is Pi=0.5*mdot*vv^2. Equating this to the power Pi=Di*V to overcome the induced drag Di, ...
EDIT::
OTOH, if one equally arbitrarily assumes that the uniform downwash velocity is that predicted by Prandtl for the 'lifting line', the area corresponding to the lift momentum mdot*vv is twice as large.

Last edited by HazelNuts39; 27th Oct 2012 at 10:43.
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