Re: Hot Air, and Compressibilty

Posted by Robert Holmes on Nov 28, 2009; 3:38pm
URL: http://friam.383.s1.nabble.com/Hot-Air-and-Compressibilty-tp4078685p4079776.html

NASA have got a Beginner's Guide to Aeronautics that's worth looking at. It's includes a section on compressible aerodynamics, which - as Peter points out - is not the regime that these turbines are operating in (as object speeds are much lower than speed of sound).

-- R

P.S. Nick - meteorologists are saying just what you think they are: a cubic meter of air down here has a higher mass than a cubic meter of air up there. That NASA site has an interactive demo called Gaslab (at bottom here) that enables you to explore the ideal gas law.

On Fri, Nov 27, 2009 at 11:30 PM, Nicholas Thompson <[hidden email]> wrote:

Yes.  And while we are at it, what does it mean when meteorologists say
that air is more dense near the surface than higher up, or that cold air is
denser than warm?

N

Nicholas S. Thompson
Emeritus Professor of Psychology and Ethology,
Clark University ([hidden email])
http://home.earthlink.net/~nickthompson/naturaldesigns/
http://www.cusf.org [City University of Santa Fe]




> [Original Message]
> From: Marcus G. Daniels <[hidden email]>
> To: The Friday Morning Applied Complexity Coffee Group <[hidden email]>
> Date: 11/27/2009 11:21:15 PM
> Subject: Re: [FRIAM] Hot Air, and Compressibilty

>
> [hidden email] wrote:
> >
> > You have to sweep your hand at a speed comparable to that of sound
> > (about 330 m/s here on earth) in order stop the air from getting away
> > and to achieve any compression.
> >
> Ok, so in one of the articles mentioned,
>
>    http://physicsworld.com/cws/article/news/40993
>
> ..it said..
>
> "What they found was that a staggered column of alternately clockwise-
> and anticlockwise-rotating turbines significantly enhances the speed of
> turbine rotation. The reason, they say, is that the presence of
> neighbouring turbines concentrates and accelerates the wind."
>
> The term `concentrate', to me, sounds like a synonym of `compress' but
> in any case `accelerate' could be true in any case.
>
> The authors of the work are Caltech aerodynamics guys, so if all you'll
> give us is, "Shut up and trust the experts", well...
>
> Is their claim impossible?
>
> Marcus
>
>
>
>
>
>
>
>
>
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============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org