[TowerTalk] Error correction: Re: Wind loading
jimlux at earthlink.net
Sun Mar 26 23:48:47 EST 2006
At 08:19 PM 3/26/2006, Jim Lux wrote:
>At 06:17 PM 3/26/2006, Michael Tope wrote:
>Cd varies as a function of Re, which in turn scales as Windspeed and
>diameter (that is, if the velocity doubles, the Re doubles...if the
>diameter doubles the Re is halved)
This is wrong.. Re is proportional to "length" * "velocity", so the latter
half of the statement is incorrect..
If diameter doubles, Re doubles...
So, bigger tubes make for bigger Re, pushing you up to the Cd=0.18, which
is what it convergest to for large Re (6" tubes in 60 mi/hr winds, etc.)
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