Wind speed calculation from a pressure setting

  • Thread starter cowpup
  • Start date
  • #1
2
0

Main Question or Discussion Point

I have been out of school a long time, so please go easy on me. If the answer is an equation with symbols or letters, could you please help define them for me?

I am trying to calculate the windspeed flowing through a tube with circular opening that is 38cm2 when the vacuum creating the wind is set at a 125pa pressure. I have the ability to change the pressure setting and am wondering if different pressures equate to different windspeeds.
The machine that creates these conditions is a Textest FX3300 Air Permeability tester. It is intended for the use of putting a fabric over the top of tube (38cm2 area opening) and measuring the air permeability of the fabric. The output measurement at these settings is in cfm.
I'm am looking for a way to equate lab results with wind speed,, is there a way to say how much wind protection a particular fabric will give you. For instance, if a fabric has 0cfm airpermeability at the above settings, is it blocking a 15mph wind?, a 30mph wind?

I do understand that in the real world, wind does not only go through your clothing , the majority of it probably goes around your body like a cylander, but it seems like that would mean a straight calculation is erring on the conservative side which would be ok.

thanks
 

Answers and Replies

  • #2
CWatters
Science Advisor
Homework Helper
Gold Member
10,528
2,294
Perhaps see..

http://www.knmi.nl/samenw/hydra/faq/press.html

That will give you a rough guide to the wind pressure for a given wind speed but how do you define "protection"?

Presumably there is a figure for the air leakage above which you consider "protection" has been lost?
 
  • #3
2
0
Thanks, I'll try that.
As far as defining "protection", under 1cfm of air permeability is generally considered insensible for windchill.
 

Related Threads for: Wind speed calculation from a pressure setting

Replies
3
Views
1K
  • Last Post
Replies
3
Views
7K
Replies
11
Views
3K
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
2
Views
7K
Replies
3
Views
3K
Replies
0
Views
788
Top