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This is an old revision of this page, as edited by Huon (talk | contribs) at 23:47, 3 July 2013 (→Help request: reply). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

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Hello, M S DIVEKAR, and welcome to Misplaced Pages! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

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June 2013

Hello, I'm Arc de Ciel. I wanted to let you know that I undid one or more of your recent contributions to Betz' law because it did not appear constructive. If you think I made a mistake, or if you have any questions, you can leave me a message on my talk page. Arc de Ciel (talk) 04:05, 30 June 2013 (UTC)

Talkback

--Arc de Ciel (talk) 11:12, 30 June 2013 (UTC)

--Another response for you on the Betz' Law issue. :-) Arc de Ciel (talk) 07:56, 3 July 2013 (UTC)

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I do accept that formula computation at 21 on page 25 is alright and gives Cp = 16/27.Here the authors - and myself did realize that we had made a mistake of not taking into consideration change in area of cross section of the wind along the path.

So the authors proceed to make corrections are recomputed by going on page 26, the authors derive Pideal as = (8/9)*(1/2)*ρ*S1*(V1^3).

Now refer to diagram at Fig 1 on page 21 where S1 is area through which wind is captured at velocity V1. So far it is fine.

Then the author uses a correction factor for area of the wind to say S = 3/2* S1 at the top of page 27. Then P ideal is recomputed as = (16/27)*(12)*S* (V1^3). Again referring to the fig 1, S – is area where the turbine blade is supposed to be located (If I change the turbine blade design – innovatively from S1 end to S2 end- this assumption is not valid), while velocity is at input end.

So are we using different factors taking area at one point and velocity along another point on the path of the wind- to justify BETZ’s formula of Cp= 16/27 ???? This is scientifically incorrect.

I personally feel that we should stop at Pideal = (8/9)*(1/2)*ρ*S1*(V1^3) which means we can extract 88.88 % of the power in the wind captured and not some 16/27 =59.26%.

May be you could consult experts and put my comments as foot note on the Misplaced Pages.

59.92.217.70 (talk) 09:05, 3 July 2013 (UTC)

Hi! I fixed your template for you, so someone should arrive shortly. As a quick note for the editor who responds, the edit in question is at Betz' law, and discussion is here (the comment above is the latest response). The article talk page seems inactive, so my recommendation is for M S Divekar to ask at Wikiproject Physics. Arc de Ciel (talk) 21:31, 3 July 2013 (UTC)

I'm not a physicist either, but for all I can tell, Betz doesn't really care about S1 or S2 at all and ignores radial velocities - it considers power extracted from the air flowing through the (assumed to be) planar rotor and doesn't bother with computing how much area that air flows through before or after it is affected by the rotor. Betz only cares about how fast that air once was, how slow it will at some point be, and about the rotor area in between. Yes, that's a simplification of what really happens, and the Betz' law article admits as much. The S₁=2/3*S factor for the optimal result can be reverse-engineered from v₁=3*v₂; in general you have ${\displaystyle S_{1}v_{1}=Sv=S{\frac {1}{2}}(v_{1}+v_{2})}$. For a more thorough explanation you may want to try the reference desk. Huon (talk) 23:47, 3 July 2013 (UTC)