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Question: drag coefficient


AlphaGeek

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How would I determine the drag coefficient of an organic shape, such as a blob of pudding or a chicken or a Looney Tunes character?

I wanted to do a blog post on the terminal velocity of Wile E. Coyote falling off of a cliff. I went back into my notes and found the following equations:

Air resistance = Fdrag = bv = cv2

VT= (mg)/b

V = VT ( 1 - e(-b/m) )

Notice the constants, b and c. I turned to google, thinking that the constants would be relatively easy to find.

It turns out, the equation for Vterminal is a little more complex than I thought.

[ATTACH=CONFIG]532[/ATTACH]

Finding V terminal involves the mass of the object, acceleration due to gravity, the density of the medium that the object is traveling through, the area effected, and, of course, a drag coefficient. In my quest to find the drag coefficient, I found that the coefficient is related to the shape of the affected surface area. The lower the drag coefficient, the more easily the object can move through the air. The following table helps illustrate this:

[ATTACH=CONFIG]533[/ATTACH]

That's fine and well if you're trying to find the terminal velocity of a UPS box falling from a cargo plane in air of know density, although there are a few complications in the Wile E. Coyote situation. My number one probelm is as follows: unless the furry critter assumes a fetal position and magically transforms his body into a perfect sphere, his coefficient is difficult to determine.

Any suggestions? :dontknow)

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