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Old 02-20-2012, 12:48 AM   #257 (permalink)
ERTW
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so...21 hours later...I realized how to drastically cut calculation time.

Results for a sharp nosed revolved template - 295 N total drag => Cd = 0.178
The frontal area is 3.0656 m^2 (60" tall, 5" ground clearance)
air speed is 30 m/s (108 kph or 67 mph)
air density at 20C is 1.204 kg/m^3

I realised that from 70% to 80% of the template is a straight section, whereas I use a curve. Phil, if you were expecting a lower Cd, I strayed from the template, as you can see, and this is what I got. This software has good correlation. I didn't want to go beyond solid models and get into surfaces, so I'll leave it at that.

It's expected, and still pleasant confirmation, to see the surface pressure *increases* near the very tip of the tail. I made the nose sharper because there was a large high pressure area on the blunt nose.

Tomorrow will be an interesting day at the University of Toronto
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The Following 10 Users Say Thank You to ERTW For This Useful Post:
aerohead (02-20-2012), BamZipPow (02-22-2012), blownb310 (02-27-2012), Cd (02-20-2012), ChazInMT (02-20-2012), KamperBob (02-21-2012), landsailor (02-21-2012), NeilBlanchard (02-20-2012), skyking (02-20-2012), Vekke (04-14-2012)