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-   -   Nan on LES dynamic models (http://www.cfd-online.com/Forums/openfoam-solving/60644-nan-les-dynamic-models.html)

sampaio March 8, 2005 13:52

Hi all, I am trying to use a
 
Hi all,
I am trying to use a dynamic model for LES, but since the first iteration I got "nan" in all solvers...
Has anyone succeeded in using dyn models?
Do I need to do anything else, other than switch the name of the model in turbulenceProperties?
(I started with the "static" model, in my case 1Eq, and than after several timesteps, switched to dyn model)
Thanks,
Luiz

hjasak March 8, 2005 13:56

Do you have a zero turbulence
 
Do you have a zero turbulence initial condition? That would do it - have a look at the files in zero directory and make sure they make sense.

Hrv

henry March 8, 2005 13:59

Which dynamic model are you tr
 
Which dynamic model are you trying? I have just tried dynSmagorinsky on the tutorial case and it ran fine.

There may be an issue with the dynamic models starting from a zero or even uniform U field. Try running with a non-dynamic model first and then restart with a dynamic model.

eugene March 8, 2005 14:03

I dont think you can yet switc
 
I dont think you can yet switch turbulence models in mid-calculation.

henry March 8, 2005 14:04

You can restart with a differe
 
You can restart with a different turbulence model, I do it frequently.

sampaio March 8, 2005 14:07

Hi Henry, It ran fine with dy
 
Hi Henry,
It ran fine with dynSmagorinski, but it blows with dynOneEq...
I did run first with a static (non-dyn) model.
Thanks a lot

henry March 8, 2005 14:10

OK, I see what is going on. T
 
OK, I see what is going on. The problem is the dynamic models do ynot currently have stabilisation in the terms average(LL && MM)/average(MM && MM) where MM may be locally (or even globally) zero. I will look at the dynOneEq... and tell you what you need to change.

henry March 8, 2005 14:51

Try this http://www.cfd-on
 
Try this

http://www.cfd-online.com/OpenFOAM_D...s/mime_txt.gif locDynOneEqEddy.C

sampaio March 8, 2005 16:41

Hi Henry, I tried but it did
 
Hi Henry,
I tried but it did not worked.
Did it work for you?
Thanks.
Luiz

sampaio March 8, 2005 16:44

Hi Henry, I tried but it did
 
Hi Henry,
I tried but it did not work.
Did it work for you?
Thanks.
Luiz

henry March 8, 2005 16:44

Yes, it worked fine for me. P
 
Yes, it worked fine for me. Put some print statements in it to check you are calling the new functions, the ones with the limiters in are at the top of the file.


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