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"Buffet" having nan value in su2

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Old   October 18, 2022, 13:27
Default "Buffet" having nan value in su2
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chandan
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Greetings everyone
I am new user of SU2. I am trying to run a cfg file for mesh generated through pointwise for SD8020 airfoil with a zero thickness flap at 0.6c with flap legth 0.3c.
On running simulation in su2 its history file is showing nan for all rows of "Buffet" column causing divergence in the simualtion. I am not able to understand that what is this "Buffet" and how can i remove this bug.
please help
regards
chandan
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Old   October 24, 2022, 12:13
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Wally Maier
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Hi Chandan,

This post may be better suited for the main forum.
As for your issue, I have doubts the "Buffet" value is causing divergence as it is an aerodynamic coefficient. Could you please your config file/ log output?

Best,
Wally
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Old   October 25, 2022, 15:23
Default BUFFET DIVERGENCE WITH Nan
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chandan
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Dear Wally
attached is the cfg file of pertaining issue. i will wait for your reply
thanks and regards
Attached Files
File Type: txt fresh_flap.txt (4.7 KB, 3 views)
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Old   October 25, 2022, 23:08
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Hi Chandan11,

Your config file looks fine. I suggest running first order (MUSCL_FLOW=NO) for a bit to see if your issue resolves. Additionally, you could run explicitly with a lower CFL number.

Can you post your log outputs or mesh? What does the flow solution look like when it begins to diverge?
This could possibly be a mesh issue as well.

Wally
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Old   October 27, 2022, 06:54
Default Su2 divergence due to "buffet" having nan
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chandan
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Dear Wally
greetings
thanks for addressing my issue.
I did as per your suggestion with respect to MUSCL_FLOW , however, still problem persists.
I am attaching my mesh file along with cfg.
regards and thanks in anticipation
chandan
Attached Files
File Type: zip for_forum_mesh.zip (94.0 KB, 1 views)
File Type: txt fresh_flap_forum.txt (4.7 KB, 1 views)
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Old   October 27, 2022, 10:52
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Wally Maier
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Interesting, I am more convinced it is a mesh issue.

On that note, it looks like the pointwise file does not want to be un-compressed. I am unable to unzip the folder, on any multiple machines strangely. Can you reupload the pw file, or maybe try the .su2 file?

Thanks
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Old   October 27, 2022, 12:09
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Dear Wally
soryy, i am not able to upload py or su2 file. can you please give me your email where i can send the same
thanks
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Old   October 28, 2022, 10:38
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Wally Maier
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After looking at your mesh, I suspect you have a few issues. First, there is no boundary layer to resolve the viscous phenomena, this will will cause issues for your heatflux walls.
Additionally, the one-dimensional flap geometry will also probably cause issues, at least I would expect it to. I would recommend looking at other viscous meshes on the su2 website to get an idea of the BL meshes.
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Old   October 28, 2022, 13:47
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thanks Wally
i'll look into it again
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