"Jim-Poncin" wrote in message
nk.net...
Occasionally we get heavy winds here, almost always from one general
direction.

I'm thinking of putting up a wind fence close to the house. I'm a little
worried that the fence might wind up creating some sort of "focusing" of
wind energy that might go to work on the roof.

Anybody know of any good sources of info on these things?

Thanks


Its hard to say if a particular fence might redirect wind to become damaging
someplace else but chances are you would not build a fence so perfectly
wrong it would tear off your roof. Almost any fence in the wind will create
turbulance but how big those eddies are and where they go is impossible to
say from here.

One thing I will add is that an evenly arranged fence top edge will make
more noise than one with randomly arranged (in height primarily) pickets.
Rnadom profile walls have been sucessfully used to mitigate freeway noise
for example. Time and time again, chaotic or random surfaces tend to allow
more smooth flow of air or water (fluid motion). Even surfaces usually
create turbulance somewhere near their edges. Unless you are also making an
art project you will need to use traditional methods and find a suitable
compromise

As an experiment, you could brace a 4x8 sheet of plywood up in the location
and test airflow around it by tossing leaves in the wind. This will be an
incomplete test but should give some guidance of what to expect.
Furthermore, you could cut shapes into the top edge of this sheet to
experiment. I assume a scale model in a wind tunnel is out of the question
;-)