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# Cd independent of Aspect ratio

Divide Coefficient of drag (Cd) by Aspect ratio of bounding rectangle of profile
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The drag is calculated by Cd multiplied by frontal area. That means Total drag has been made indpendent of area by dividing drag by area. Why not do the same for aspect ratio of the bounding rectangle of the shape. Ex. if aspect ration of ( Height vs. Width) is 1.7 :: 1; Then divide Cd by 1.7; Thus we can calculate Cd easily by large amount of shapes which are similar but are only streched in X or Y direction.

This idea relies on the asumption that Cd is linearly proportianl to ratio of Height to width of the bounding rectangle of the profile shape.

 — VJW, Feb 28 2012

Mr. Reynolds may fit in there somewhere.
 — FlyingToaster, Feb 28 2012

Reducing to simple shapes is a fairly standard engineering approximation. That being said, it is, at best, an approximation for real world objects.
 — MechE, Feb 28 2012

 From the category, I assume you're talking about coefficient of drag in relation to an airplane wing, so:

 // Why not do the same for aspect ratio of the bounding rectangle of the shape.//

 A) because your method will require the number of 'similar' XY shapes to equal 10 to the Mandelbrotth degree.

 B) the aspect ratio of most modern wings changes slightly from base to tip, so to get an accurate model you'll have to use XYZ shapes.

 C) even if you do this, the resulting figure will still be only an approximation of the total frontal area, albeit a very close one.

D) there is no rhinoceros involved in this method.
 — Alterother, Feb 28 2012

I think there is definitely a physical constraint (i.e. rotation) on having the data-bearing area of a CD circular. It can have an unusual aspect ration outside of this area but within the overall circular shape of a full size CD (like a business card CD which is baked).
 — pocmloc, Feb 28 2012

 Is it a bad thing that I read the title and thought of a CD player that could play multiple size audio CDs?

Sorry, music is my life.
 — Psalm_97, Feb 28 2012

I'm sure I had an anno here somewhere...
 — MaxwellBuchanan, Feb 28 2012

I went looking for images of drag queens and kings, but the possibilities were too endless to link to.
 — normzone, Feb 28 2012

 [Ps97], no matter what size, all circular CDs have the same aspect ratio.

Though, if music is your life, what are you doing using CDs? Or did you mean to write, mechanical imitation of music is your life?
 — pocmloc, Feb 28 2012

//circular CDs// - but if we created elliptical CDs, which, of course, should obey Kepler's orbital laws of sweeping out equal areas in equal times, making them able to maintain a continuous bit rate, assuming we can halfbake a variable-geometry read head... Hey, a rhinoceros!
 — lurch, Feb 28 2012