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re: frugal storm shelters?
10 may 2000
sojourner wrote:
>...nor do i feel the least bit obligated to explain my engineering
>and educational background to you.
posting here can naturally lead to all sorts of curious questions
as to whether you know anything about what you are talking about... :-)
>your obvious lack of grasp of the simplest laws of physics makes
>that a waste of time.
perhaps. here's something simple that i don't understand:
"steve spence" wrote:
>http://www.monolithicdome.com/articles/survive/index.html
>http://www.webconx.com/shelter.htm
>a wind of 70 miles per hour blowing against a 30 foot tall flat walled
>building in open flat terrain will exert a pressure of 22 pounds per square
>foot (see sidebars). if the wind speed is increased to 300 miles per hour
>the pressure is increased to 404 pounds per square foot (psf)...
now i've been under the impression that the velocity pressure of a v mph
wind is about v^2/400 psf, so a 70 mph wind exerts about 12 psf if
you stop it completely, and 300 mph only makes 225 psf. how can the
shape of the object that stops it increase that? it seems to me that
the maximum pressure would be developed by a very large very tall wall,
and a shorter wall would experience less pressure...
then again, those monolithic folk believe in "dynamic r-values..."
nick
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