Chris:
In the "Uniform Building Code" used in the US the wind pressure is a
function of a variable called the stagnation wind pressure, Qs. This
wind pressure is modified by factors such as exposure, or fetch, and
height above the ground and the geometric shape of the particular
structure in question.
This stagnation wind pressure value, Qs, is a function of the wind
velocity. In the old imperial units, miles per hour, is as follows;
Qs = 1/2 Rho V*V where Rho is the mass density of air
and V is wind velocity.
This is also Bernoulli's equation.
reduced to usable values this translates to
Qs= 0.00256*V*V when V is in miles per hour
Qs is pounds per square foot.
don't forget that you can reduce the value due to geometric shape of
structure. In the case of an antenna assuming a round cross section 2
inches or less in diameter it is apporpriate to use a factor of 0.8
Hope this helps.
Hank / KR7X
______________________________ Reply Separator _________________________________
Subject: [TowerTalk] Formula?
Author: K7LXC@aol.com at ~INETMAIL
To: <towertalk@contesting.com>
Date: 5/28/98 1:09 PM
>From Chris, ZS6EZ --
" I'm looking for the proportionality constant (c) that relates wind
speed (v) and antenna surface area (A) to the lateral force on the
antenna (F), i.e. F = cAv.
Any ideas, please? "
Tnx, Chris ZS6EZ
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