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-   -   run form mapField (http://www.cfd-online.com/Forums/openfoam/68779-run-form-mapfield.html)

andrea.pasquali October 1, 2009 11:40

run form mapField
 
Hi everybody,

I got a solution with a coarse mesh. I mapped it on a finest mesh with mapFields command, and it's ok.
Then I want to run with the finest mesh from the mapped solution, but at the beginning I obtain "floating point exception" and the run dies.
What's my problem?

Thanks for any reply,

Andrea

harishg October 1, 2009 19:19

Floating point exception usually points to a divide by zero. Do you change the BC between the coarse and fine mesh? Did it show the exception on the first timestep? What model and BC are you exactly using to study your problem?

andrea.pasquali October 5, 2009 07:41

Hi Harishg,
Thank you. At the beginning, when I start the run whit fine mesh, the solver read in file T a "nan" term. I changed it with zero value and maybe it's this that give me the problem. I'm using the same condition between coarse and fine mesh.
What means "nan" value? Can I try to change it with 0.000001 (small but no zero value)?

Thanks

Andrea

lord_kossity October 5, 2009 08:35

Hi Andrea,

nan means "not a number". This term usually stands for infinity. So replacing it with a small number won't help you out!

Regards,
Andreas

harishg October 5, 2009 10:59

My guess is that the coarse mesh run itself did not converge and produced Nan term. Hence the mapping transfers it to the fine mesh too. Check the files in the coarse mesh for the Nan term.

andrea.pasquali October 5, 2009 11:47

Thank Andreas and Harishg,
I saw my mapped files and I got "nan" value in epsilon, k, rho and T. I got also many "0" values; like this:

0
0
0
0
0
0
0
0
2.07259e-315
2.122e-314
99967.2
99967.2
6.2051e-315
nan
99934.6
6.2051e-315
0

In coarse mesh run I don't got "nan" or "0" value. It's a good solution and I reached small residuals. But I didn't say you that I obtained this solution with Openfoam1.5.x; instead I mapped it with last Openfoam1.6.x.
Can this be a problem, mapping OF15x solution on OF16x?

Thanks

Andrea


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