Quote:
Originally Posted by Daox
I find it very amazing that the little vent increases drag by over 10%.
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It might help once you realize how big the flat plate area (i.e., the CdA) of the car is. It's not that big - 0.30 equates to 30% of the car's frontal area. Which is probably on the order of 6-8 square feet. Compare other vehicles
here.
If you understand that drag
coefficients for really, really, ugly things (aerodynamically) such as the Eiffel Tower are 1.8-2.0, and that routing air through the engine bay, under your car etc is probably just as ugly, what is 10% of the CdA and hence what is the actual area of grille that would be blocked to achieve the difference?
10% of 7 square feet is 0.7 square feet. If we take the drag coefficient of that particular area as 2 (not a bad assumption), you only need 0.35 actual square feet of grille to get the difference. That's the difference a "little vent" can make.