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-   -   iteration no. explodes, solution diverges (http://www.cfd-online.com/Forums/openfoam-solving/107404-iteration-no-explodes-solution-diverges.html)

adamsinan September 26, 2012 09:19

iteration no. explodes, solution diverges
 
Hi everyone,

after few steps from run begin, the No. of iterations for Ux, Uy, Uz, k and epsilon begin to explode then Co No. also explodes & the solution diverges.

I'm using OF2.1, k-epsilon model, pisoFoam, 8-nodes.
Thanks in advance for help.
(please, tell me if you need more infos)

treima September 26, 2012 09:43

Hi,

some more information would be useful, i.e.
- timesteps
- geometry
- size of cells
- boundary conditions
and so on ;).

Without you just cam guess, why it doesnīt work!

adamsinan September 26, 2012 10:11

Hi Treima,

I have a flow around a cylinder (inlet, outlet, no-slip wall bed),
cells no. is 4.5 million,
time-step: I tried different values (from 1e-5 to 0.01 ) (the same happened with all, except sometimes more working iterations).

I tried the same case (finer mesh) in OF1.6.x & it worked...I switched to OF2.1 because I have problem with parallel run in the older version.

Please, tell me if you need more info.

treima September 27, 2012 02:45

At the first moment i thought your timestep ist to large or your boundary conditions are wrong. But if the case worked in an older version of OpenFOAM, this is a little bit confusing. I donīt know, if there are any changes in OpenFOAM or in your case, which cause the mistake. Iīm not so familiar with the older versions...

And always give as much informations as possible!


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