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-   -   I have used SU2 for DLR F6. but it seems that the ajoint result is weird?? (https://www.cfd-online.com/Forums/su2/150947-i-have-used-su2-dlr-f6-but-seems-ajoint-result-weird.html)

chenbojian April 1, 2015 12:10

I have used SU2 for DLR F6. but it seems that the ajoint result is weird??
 
2 Attachment(s)
My F6 mesh is generated by using the nasa drag predict geometry.The Reynolds length is 0.1412. Reference aera is 0.0727.The CFD result is match with the experiment data. But the ajoint result is weird and then SU2_DOT calculate all gradients ZERO.
This is my ajoint result of drag. The Surface_Sensitivity seems not right?
And my config file.

Tommy Chen April 2, 2015 11:18

Quote:

Originally Posted by chenbojian (Post 539502)
My F6 mesh is generated by using the nasa drag predict geometry.The Reynolds length is 0.1412. Reference aera is 0.0727.The CFD result is match with the experiment data. But the ajoint result is weird and then SU2_DOT calculate all gradients ZERO.
This is my ajoint result of drag. The Surface_Sensitivity seems not right?
And my config file.

Could you post the output history ?

hlk April 2, 2015 14:46

Quote:

Originally Posted by chenbojian (Post 539502)
My F6 mesh is generated by using the nasa drag predict geometry.The Reynolds length is 0.1412. Reference aera is 0.0727.The CFD result is match with the experiment data. But the ajoint result is weird and then SU2_DOT calculate all gradients ZERO.
This is my ajoint result of drag. The Surface_Sensitivity seems not right?
And my config file.

I suggest double checking the design variable definition and smoothing options.
Design variables: they should cause a deformation to the surface specified in Marker_Designing
Smoothing: start with no smoothing

chenbojian April 2, 2015 22:16

Quote:

Originally Posted by Tommy Chen (Post 539701)
Could you post the output history ?

Sorry,my old history is overwritted. But I find it is not converge. And I calculate again, it is converging very slow. I don't have any experience about calculate the surface sensitivity. What is the right surface sensitivity range? I think the range I posted is not right.

chenbojian April 2, 2015 22:23

Quote:

Originally Posted by hlk (Post 539722)
I suggest double checking the design variable definition and smoothing options.
Design variables: they should cause a deformation to the surface specified in Marker_Designing
Smoothing: start with no smoothing

I think my Design variables are right. And also the FFD infomation. I tried to give a specified DV_VALUE to view the deform. It deformed successfully. So I doubt my Adjoint result is wrong. What dose the surface sensitivity should be? I have viewed the M6 result in TestCase. Its surface sensitivity range is (-50,50). Will this value change very large in deferent case??

Tommy Chen April 2, 2015 22:33

Quote:

Originally Posted by chenbojian (Post 539747)
Sorry,my old history is overwritted. But I find it is not converge. And I calculate again, it is converging very slow. I don't have any experience about calculate the surface sensitivity. What is the right surface sensitivity range? I think the range I posted is not right.

If the mean flow has not converged, you probably won't expect the adjoint to either converging or accurate.

chenbojian April 2, 2015 22:51

Quote:

Originally Posted by Tommy Chen (Post 539749)
If the mean flow has not converged, you probably won't expect the adjoint to either converging or accurate.

The mean flow is converged. I have compared it to the experiment data. I mean the adjoint result is not converged.

chenbojian April 10, 2015 23:18

Problem Solved
 
The reason is just because the DV_DEFINITION setting is not right in my config file. The FFDtag is WING_BOX but my set is 0.


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