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Old 04-07-2012, 02:47 PM   #13 (permalink)
aerohead
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round/square

Quote:
Originally Posted by drmiller100 View Post
every vehicle made in the past 20 years has rounded rear corners. I think you round them in hard, and let the flow stay attached for however long it does, further reducing your rear area.

I don't understand why you would want them squared off. Squared off is just going to make more turbulence over a bigger area.

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I'll try and have another pictorial drag table ready for next Saturday which has some wind tunnel data for a 12-meter bus of square and radiused rear vertical edges.
Rounding the rear actually drops the drag on the bus,from Cd 0.325,to 0.314,although interior space is compromised a bit.
Kamm's research pretty much convinced everyone just to truncate the body,chopping it off as with a loaf of bread.
This gives a perfect separation line,the added length allows a bit more pressure recovery, and makes a very stiff rear bulkhead which can be constructed lighter.
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