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Old 05-03-2011, 01:02 PM   #34 (permalink)
justjohn
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Excellent work mort! That study is definitely more applicable to what we want to know. It would still be be nice to have a single screen with very small openings tested at full highway speeds, but I think it's a pretty safe bet this estimate is reasonably accurate:

Quote:
Originally Posted by mort View Post
Window screen might have a Cd of about 5 for highway speeds. Or 5 times worse than a flat plate.
I also found it interesting how drastically the Cd drops with more open screens. The cliff notes for people who can't be bothered to look at the study:

At 47mph single screen
Open area/Cd
34% ~4.8
47% ~3.0 and barely changes with speed
57% ~0.8 and barely changes with speed
61% ~1.0 and barely changes with speed
67% ~0.4 and barely changes with speed
77% ~0.2 and barely changes with speed
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