Classical NACA0012 aerodynamics calculation an not converged in Fluent

- March 23, 2022 at 2:17 pm
  
  Susan
  Subscriber
  
  Dear all,
  My case attached
  naca0012.rar
- March 24, 2022 at 3:15 am
  
  Keyur Kanade
  Ansys Employee
  
  As Ansys Staff, we can not download attachments. Please upload images using upload image functionality.
  The min orthogonal quality should be above 0.1 to proceed to solver. If it is less than 0.1 then please improve the mesh.
  First check the locations of the bad elements. Please see following video for the same.
  
  https://www.youtube.com/watch?v=ZDADSSN8hOs
  
  Once you have locations, please check if you can improve mesh using different mesh sizing. Please see following video.
  
  https://www.youtube.com/watch?v=w4q6q8nKF3U
  
  If this does not help, you may need to check if you can use pinch control or virtual topology.
  
  https://www.youtube.com/watch?v=wdKMqfJV1Ys
  https://www.youtube.com/watch?v=RELLrEJ9chg
  
  If this does not help, please go to geometry and modify or simplify geometry at those locations in SpaceClaim.
  Regards Keyur
  How to access Ansys Online Help Document
  Guidelines on the Student Community
- March 24, 2022 at 4:25 pm
  
  Susan
  Subscriber
  
  Hi, Thank you so much for your help. I have solved that and it's converged
  However, I got the wrong Cd value when AOA=-12┬░, my result is around -0.23.
- March 24, 2022 at 4:40 pm
  
  Rob
  Ansys Employee
  
  As the coefficients are linked to the reference values I'd start there.
- March 24, 2022 at 4:56 pm
  
  Susan
  Subscriber
  
  Then I changed AOA=10┬░ and I got Cd around -0.17. My reference values are as shown and they were set to make Re=6e6.
- March 24, 2022 at 5:01 pm
  
  Rob
  Ansys Employee
  
  The drag or the reference values? Please follow the various tutorials that cover NACA aerofoils of various types.
- March 24, 2022 at 5:16 pm
  
  Susan
  Subscriber
  
  I don' think the drag coefficient is correct. It is different from NASA experiment.
  But I set the reference values as https://su2code.github.io/tutorials/Inc_Turbulent_NACA0012/.
  Should I change reference values when calculate Cd? But the value of lift coefficient Cl is correct.
- March 25, 2022 at 11:28 am
  
  Rob
  Ansys Employee
  
  If lift is correct also check mesh resolution both on the wing but also in the wake region. Without opening the link it's hard to comment, how does the set up compare to the video/example in Fluent's Help?
- March 29, 2022 at 1:39 pm
  
  Susan
  Subscriber
  
  Thanks, Rob, will do.

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