Hi justjohn,
This is good. Looking at 80 and 100 mesh. Window screen is usually 14 or 16 mesh, so this is a lot tighter than what I think most are interested in here.
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Attached is the key graph1. Note drag goes from 6 to about 1 as the air speed increases! That's the opposite from what I expected.
I found a
paper at the University of Southern Queensland about fire supression using double layers of wire mesh. These tests were on larger mesh, the wire about twice as big as window screen and about 10x10 mesh was the smallest with 34% porosity. Attached is the cherry-picked graph2 showing drag coefficient of around 4 but generally constant for air speed. The other tests show that wire size and porosity are very important for drag. Finer wire and less open space increasing drag. Large wire and large mesh, even just 4x4 has a drag well below 0.5
Window screen might have a Cd of about 5 for highway speeds. Or 5 times worse than a flat plate.
-mort