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Old 07-04-2014, 01:46 AM   #23 (permalink)
ecomodded
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Quote:
Originally Posted by Patrick View Post
FYI, a quick approximation for Reynolds number for objects in air at sea level is
Re = Length in feet X Speed in mph X 10,000.

So a 15 ft long car at 50 mph would have a Reynolds number of 15 X 50 X 10,000 = 7,500,000.

A 1/32 scale model in a 50 mph wind tunnel would have a Reynolds number of 15 X 1/32 X 50 X 10,000 = 234,375, or 1/32 of the full-size car. If you double the wind speed in the tunnel to 100 mph, the Re would be 1/16 of the full-size car. See the relationship?
Thanks for the insight.

I do see the relationship , thanks for that and the formula for scaling.

How the Re interacts with vortexes is still unclear , If you could simplify that , It would be much appreciated.
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