Cl-alpha, 3d airfoil problem.

levonlarson · February 14, 2011, 19:55

I am trying to determine dCl/d(alpha) for a 3d airfoil however Cl is barely changing (0.38-0.42) as I vary alpha (0-10 degrees), any help?

I only need preliminary results so my mesh is fairly coarse.

Thanks.

montag dp · February 15, 2011, 03:07

If you are reporting Cl from the monitors, are you sure your reference values are correct?

If that's not it, I'd try refining your mesh first.

levonlarson · February 15, 2011, 10:29

My reference values are good, Fluent is simply underestimating the force produced by the airfoil as it changes angles. I also forgot to mention that my first mesh refinement did not fix the problem.

I am very closely following the 2D wing tutorials, at this point my wing is just a 2D airfoil that has been extruded.

February 14, 2011, 19:55	Cl-alpha, 3d airfoil problem.	#1
levonlarson New Member Levon Join Date: Feb 2011 Posts: 3 Rep Power: 15	I am trying to determine dCl/d(alpha) for a 3d airfoil however Cl is barely changing (0.38-0.42) as I vary alpha (0-10 degrees), any help? I only need preliminary results so my mesh is fairly coarse. Thanks.

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February 15, 2011, 03:07		#2
montag dp Member Join Date: Jul 2010 Posts: 38 Rep Power: 16	If you are reporting Cl from the monitors, are you sure your reference values are correct? If that's not it, I'd try refining your mesh first.

February 15, 2011, 10:29		#3
levonlarson New Member Levon Join Date: Feb 2011 Posts: 3 Rep Power: 15	My reference values are good, Fluent is simply underestimating the force produced by the airfoil as it changes angles. I also forgot to mention that my first mesh refinement did not fix the problem. I am very closely following the 2D wing tutorials, at this point my wing is just a 2D airfoil that has been extruded.