On Tue, Feb 05, 2008 at 10:13:37AM -0500, Norm of Bandersnatch wrote: > 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.
Well vacuum can only get as large as ambient pressure, since it's just a removal of said pressure. Strictly speaking, the plane is lifted entirely by pressure on the underside of the wing, it's just that some of it is ambient and therefore ordinarily balanced out by pressure on the top of the wing. > 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 And here I thought that it was E=1/2 mv^2 :) > 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. In order for the relation between E and v to remain quadratic, m needs to be constant with respect to v. Given that twice as much air blows past you in a 10kt breeze than in the same period (with the same temperature and pressure) in a 5kt breeze, I think it's fair to assume m to be proportional to v and therefore provide the claimed cubic relation (though I almost didn't catch that myself). Cheers, Kris -- Kris Coward http://unripe.melon.org/ GPG Fingerprint: 2BF3 957D 310A FEEC 4733 830E 21A4 05C7 1FEB 12B3 _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard To subscribe send an email to [EMAIL PROTECTED] To unsubscribe send an email to [EMAIL PROTECTED] The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
