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Old 04-09-2008, 11:35 PM   #17 (permalink)
Gone4
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Quote:
Originally Posted by LostCause View Post
Not 100% sure, but air density values pulled out of books tend to be at STP. Standard temperature and pressure are not common values one would see at sea level. For example, I believe standard temperature is 0C...

I don't know how big a difference the true air density would make on Cd accuracy, but if the value was pulled out of a book it is probably off.

- LostCause
STP varies based on the book. 0 C is only for chemists generally. In engineering it is often anywhere from 60 F-70 F. Most common in studies of fluids is 68 F or 20 C as they intercept exactly at the point and it's a pretty common air temperature. However, humidity will affect this greatly since usually they assume there is no vapor component.
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