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Old 07-19-2008, 12:17 AM   #95 (permalink)
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Originally Posted by Bicycle Bob View Post
I wonder if dust is shaking off that surface.
I'd be happy to observe under-tail tufts for you if we were neighbors, but perhaps the easiest do-it yourself approach would be to tape a digital camera under the tail. Even a very basic one will usually make movies a few minutes long.
I've heard that another quick test for turbulent/laminar flow is the speed of evaporation. If you wet your car and drive a bit, the last wet, shiny areas have laminar flow.
Another method (which I have been thinking about) would be to use baby powder (or equivalent) and pat it down on the surfaces you want to check. Then drive at the speeds you want to check and Presto!, if it gets cleaned off, laminar flow! So if you live on a dirt road and your car stays nice and clean, chances are, you have good laminar flow the entire way.
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