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Negative Volumes SU2_DEF for a wing-body junction case

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Old   December 17, 2014, 12:04
Exclamation Negative Volumes SU2_DEF for a wing-body junction case
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Zen
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Zeno
Join Date: Sep 2013
Location: Delft, The Netherlands
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Dear Developers,

I was testing the SU2_DEF capabilities in terms of deformation of a mesh at the wing-body corner. My wing is a Rood wing and my body is a simple flat plate attached to it. The mesh is completely structured and more info about the case can be found here:

http://cfd.mace.manchester.ac.uk/cgi...html&1&0&0&0&0

I want to perform a deformation of the flat plate in the spanwise direction only (y-axis). Attached is the configuration file I used.
To test SU2_DEF I moved one design variable in the spanwise direction and checked the surface mesh deformation and the volumetric mesh deformation (see figures). The surface mesh deformation is fine, however, the volumetric mesh deformation produces negative volume cells from the first linear iteration.

I then reduced DV_VALUE of a orderd of magnitude every time until I got no negative volume cells. However, this happened for a DV_VALUE=-0.00001 meaning the deformation of the flat plate is negligible. The aim of my work is to optimize the junction area and I am expecting large deformations of the body in that area. Hence, I can't afford having such a small DV_VALUE (which, if I understood correctly, it will take the value of the scaling factor of the OPT_OBJECTIVE term) because it would take an awfully large number of cycles to get to the final shape and I expect negative volume cells to pop up anyways at a certain point.

Do you have any suggestions on how to solve this problem?

Thank you very much,

Zeno
Attached Images
File Type: jpg Surface.jpg (62.4 KB, 23 views)
File Type: jpg SurfaceFFD.jpg (89.5 KB, 27 views)
File Type: jpg Volume.jpg (97.8 KB, 23 views)
Attached Files
File Type: txt cfg.txt (18.3 KB, 15 views)
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Tags
junction flows, mesh deformation, negative volume cells, su2_def


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