Could be mass delusion. Could be that the wind generator sellers are
trying to make their products appear more valuable than they are, a common
larceny these days.
For years we were told that airplanes fly because of the vacuum generated
on the top of the wing, only lately have they admitted that the great
majority of lift is pressure on the bottom of the wing. (Flat-winged model
gliders do fly.) Sounds like they were trying to capitalize on the "gee
wizz" factor of the suction generated by the Bernoulli effect of the wind
over the curved top of the wing while ignoring the fact that several more
times lift is due to the pressure on the bottom.
As for the wind generator question, for me, E=MV^2 is still a valid law of
physics. When the wind doubles in speed, the wind contains four times the
energy. If the wind generator is 100% efficient and extracts all the
energy possible then the output also goes up four times. I will not
believe the cube thing until I see it proven clearly enough for my mind to
accept it.
I've been told that concrete don't float too...
Norm
S/V Bandersnatch
Lying Julington Creek FL
30 07.72N 081 38.4W
> [Original Message]
> From: Arild Jensen <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Date: 2/1/2008 1:16:54 PM
> Subject: RE: Look. It's a Freighter. It's a Sailboat. It's. Both
>
>
>
> > -----Original Message-----
> > From: Norm of Bandersnatch [mailto:[EMAIL PROTECTED]
> >
> > Arild,
> >
> > That just does not make sense to me. If the wind energy goes up to the
> > square of the wind speed how can the generator output go up to the cube
of
> > the wind speed? How can the generator produce more energy than the wind
> > inputs to it? I have never known a device that outputs more
> > energy than is input.
>
>
>
> REPLY
> Norm it took me a bit to realize where I got it wrong.
>
>
> Simple wind resistance is the push on an area equal to the cross sectional
> area presented by the wind mill.
> For purposes of this discussion, its the swept disk are of the propeller
> blades or some such thing.
>
> This swept area does not change with speed.
> According to empirical data the resistance increases as the square of
> speed. i.e. double the speed 4 times the resistance.
>
>
> Generator output is a curve. It increases quite steeply until the abrupt
> cut-off at some maximum RPM.
>
> Evidently the tests indicate this power output increases according to the
> cube.
> Every website says the same. Either its true or we have a case of mass
> delusion where everybody imagines the same wrong thing.
>
> Arild
>
>
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