On Sun, Jul 06, 2003 at 07:22:39PM +0000, Robert J. Chassell wrote:
> What is the air pressure near the center of a spinning O'Neil type > space habitat when the pressure at the rim is 1 atmosphere?
> What is the equation that tells you the pressure?
Tricky. The only way I know of to get a simple equation is to make a couple approximations:
(1) The temperature of all the air is the same, 300K (2) The air all rotates with the endcaps, speed proportional to radial distance from center
In that case, the formula I come up with is
P = P0 ( 1 - h/R ) ^ ( m v^2 / k / T )
where h is the distance above the "floor" of the habitat. If we make another approximation that the air is just N2 molecules,
FWIW, the usual assumption for using the ideal gas laws re: Earth's atmosphere at low altitudes is that it behaves as an ideal gas with a molecular weight of 29 (a average of 78% N2 with a molecular weight of 28 + 21% O2 with a molecular weight of 32 (and the 1% Ar with an atomic weight of 40 is generally ignored)).
-- Ronn! :)
Ronn Blankenship Instructor of Astronomy/Planetary Science University of Montevallo Montevallo, AL
Disclaimer: Unless specifically stated otherwise, any opinions contained herein are the personal opinions of the author and do not represent the official position of the University of Montevallo.
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