Negative Cd - drag

Centurion2011 · September 8, 2011, 07:42

I get negative values of Cd when I do simulation of airflow over sharp body. How can it be explained?

husker · September 9, 2011, 13:43

Hi

What does it look like your sharp body?
What is the value of negative Cd?

Centurion2011 · September 20, 2011, 08:22

body is projectile shrapnel (random shape). Cd looks OK, but only negative. I used sine and cosine projections of streaming velocity so I guess that has something to do with it

Centurion2011 · September 22, 2011, 07:06

I have found solution for this. When you correct values for Force componnents in Reports, then Cd is positive and OK.

September 8, 2011, 07:42	Negative Cd - drag	#1
Centurion2011 Member Join Date: Jul 2011 Posts: 78 Blog Entries: 1 Rep Power: 18	I get negative values of Cd when I do simulation of airflow over sharp body. How can it be explained?

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September 9, 2011, 13:43		#2
husker Member Join Date: Mar 2009 Posts: 85 Rep Power: 17	Hi What does it look like your sharp body? What is the value of negative Cd?

September 20, 2011, 08:22		#3
Centurion2011 Member Join Date: Jul 2011 Posts: 78 Blog Entries: 1 Rep Power: 18	body is projectile shrapnel (random shape). Cd looks OK, but only negative. I used sine and cosine projections of streaming velocity so I guess that has something to do with it

September 22, 2011, 07:06		#4
Centurion2011 Member Join Date: Jul 2011 Posts: 78 Blog Entries: 1 Rep Power: 18	I have found solution for this. When you correct values for Force componnents in Reports, then Cd is positive and OK.