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-   -   Incorrect calculation of forces/moments coefficients with older versions of SU2 (http://www.cfd-online.com/Forums/su2/122082-incorrect-calculation-forces-moments-coefficients-older-versions-su2.html)

diwakaranant August 12, 2013 03:10

Incorrect calculation of forces/moments coefficients with older versions of SU2
 
2 Attachment(s)
Hi SU2 Team

I recently took part in validation study for a trapezoidal wing geometry
using SU2 version 2.0.

The forces/moments coefficients predicted by SU2 2.0 were erroneous.
In fact upto SU2 version 2.0.4, the forces/moments calculations are incorrect.
SU2 2.0.5 is giving correct values of forces/moments coefficients.

I am attaching CL and CD comparison for SU2 versions 2.0, 2.0.4 and 2.0.5
obtained for same mesh and configuration file.

SU2 2.0.5 is giving correct results (matched with experimental values)

Please look into it.

Thanks
Anant Diwakar

fpalacios August 16, 2013 01:40

Dear Anant,

Thanks a lot for your feedback. We need more details but, my two cents that the force integration was done on an open surface. If you review the documentation, the original version of SU2 requires a close surface for force integration. Some colleagues from the open-source community asked us to extend this capability, and it will be added to the new release (as you pointed out it is already in the current developer's release).

In fact, SU2 is evolving at an amazing velocity and SU2 v3.0 "eagle" will be a landmark in the open-source CFD community. We are improving all the features of the code, and the GitHub repository (https://github.com/su2code/SU2) is boosting the communication between developers around the world.

Best,
Francisco

PS.- Just to be sure that we have found the solution to your problem. Could you please send us the grid and the config file that you are using? Thanks!

Quote:

Originally Posted by diwakaranant (Post 445085)
Hi SU2 Team

I recently took part in validation study for a trapezoidal wing geometry
using SU2 version 2.0.

The forces/moments coefficients predicted by SU2 2.0 were erroneous.
In fact upto SU2 version 2.0.4, the forces/moments calculations are incorrect.
SU2 2.0.5 is giving correct values of forces/moments coefficients.

I am attaching CL and CD comparison for SU2 versions 2.0, 2.0.4 and 2.0.5
obtained for same mesh and configuration file.

SU2 2.0.5 is giving correct results (matched with experimental values)

Please look into it.

Thanks
Anant Diwakar


diwakaranant August 16, 2013 04:17

Hi Francisco

Thanks for the reply.

Regarding surface integration of forces and moments, some of the surfaces
were excluded while calculating CL, CD etc. This might be the reason
for erroneous values of Cl, Cd with earlier versions of SU2,
as mentioned by you.

Also with SU2 v 2.0.5, there is an issue regarding writing flow data files.
Refer to this post :

http://www.cfd-online.com/Forums/su2...tml#post445629

When will SU2 v 3.0 be released ? Please include RANS optimization
on Onera wing as one of the testcases.

Thanks
Anant


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