A question about fluid dynamics

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terje
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A question about fluid dynamics

Post by terje » Sat Dec 30, 2006 8:09 pm

Hi every one.

I’m trying to understand the basics of fluid dynamics, and hope there is some here one who can help me explain this.

So let’s see if I understood this correctly.
An air stream blowing across a surface would cause a lower pressure on the surface then as if the air where at rest. If the surface where perforated with small holes, and the air under the surface where still. Then the air stream would pull air trough the holes due to the venturi-effect. Now, if the perforated surface where the top of an air tight box, this would cause an under-pressure in the box. Is this correct?


So this is my question: How do I calculate these pressures, with different airspeeds? Say, 1m/s 5m/s and 15m/s.
I assume there is 4 different pressures to take in to account.
P1: air at rest, this could be normal atmospheric pressure at sea level.
P2: pressure on a cross section, perpendicular to the stream. Guess this would be the ram pressure.
P3: pressure on a point drifting with the stream.
P4: pressure in the box.
:)
/Terje
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mk
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Post by mk » Wed Jan 03, 2007 5:15 pm

Would not (hydro-)dynamic pressure or Bernoulli or gas pressure represent suitable keywords for a first search?

Sadly I cannot help you out immediately right now.
mk

leo
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bernoulli search

Post by leo » Wed Jan 03, 2007 10:06 pm

If you do a search watch out for incorrect explanations see the following links.

airfoil

nasa

nasa

google search

terje
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Post by terje » Fri Jan 05, 2007 7:07 am

Thanks.
I also found this site with, in my opinion, good and basic explanations of physics.
http://hyperphysics.phy-astr.gsu.edu/hbase/bercon.html
I’m still struggling to grasp the concepts, but I’ll get trough it.The math is not my strongest side. :)
http://home.earthlink.net/~mmc1919/vent ... _math.html
/Terje

mk
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Post by mk » Fri Jan 05, 2007 10:18 pm

Some nice links "leo"!

"Terje", www.hyperphysics.com is not that bad.
Best of luck!
mk

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