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Re: Topographic Effects
- To: seaint(--nospam--at)seaint.org
- Subject: Re: Topographic Effects
- From: Jnapd(--nospam--at)aol.com
- Date: Thu, 28 Feb 2008 12:50:15 EST
That is correct...hill rises 500' behind and to the left of the house and
60' behind and to the right of the house.
In a message dated 2/28/2008 9:45:47 A.M. Pacific Standard Time,
understand correctly, the SFR sits in an amphitheater/canyon where the hill
rises 500' behind the house, but only 60' to the side of the
On Wed, Feb 27, 2008 at 6:19 PM, <Jnapd(--nospam--at)aol.com
If the wind direction encompases 180 degree sector towards
the house; behind the house 90 degrees is as I stated before and 90 degrees
the hill rises only 60' . Do you still feel your numbers are more
correct or some where between ?
house is at 1000' with another 500' above (at 45 deg), then Lh =
750' That would change up the numbers a bit.
K1 = 0.43 (2D
K2 = 0.96 for x/2H = 500'/2*1500' = 0.167
K3 = 0.44 for
z/2H = 1000'/2*1500' = 0.333
Kzt = (1+K1K2K3)^2 = 1.40
partially enclosed is reasonable. Your other assumptions
also seem reasonable.
On Wed, Feb 27, 2008 at 2:44 PM, <Jnapd(--nospam--at)aol.com
Another fun wind question a bit winded but here goes.
I have a 2 story house on the side of a hill. The H to the house is
1000' and Lh= 500' continuing up the hill another house is 60' above
mine and 100' horizontally away. The hill continues another 500' above
this house. The hill slope is approximately 45 degrees.
The house is 22' tall and 64' diameter with 3' tall 20' diameter
Clerestory on roof; both roofs are flat.
H/Lh=2.....by footnote 2 ....K1=.43 ( because hill
continues aboe my house ) yes/ no ??
since H/Lh > .5 the Lh becomes 2H for next calculations.
X/2H = 10/2000 =.02.........K2 =1
Z/2H = 22/2000 = .011......K3 =.78
Kzt = 1.78
Kd = .95 or .85
Johnson & Nielsen Associates