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HELP DIVERGENCE NITA!!

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Old   October 1, 2007, 10:59
Default HELP DIVERGENCE NITA!!
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Hadi
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Hi to all,

I am running, LES channel flow, i ran K-epsilon by fixing a constant flow rate, and then i applied the perturbation,when running LES, after few iterations the bulk velocity will increase from 1m/s to 30 m/s ,then it changes its direction,and the simulation blows!! By looking to the residuals the contiuity is always increasing.

I ran the same simulation using another code and i didn't face any problem, so i think the mesh is ok, and the courant number is less then 0.25! can you please tell em what might be wrong.

Any help will be appreciated!

Cheers Hadi
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Old   October 2, 2007, 05:18
Default Re: HELP DIVERGENCE NITA!!
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Jim
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Do you encounter reversed flow problem? And does the problem come from the near-wall?
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Old   October 2, 2007, 06:23
Default Re: HELP DIVERGENCE NITA!!
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Hadi
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Well maybe i found the solution, i am not sure though. When you specify a constant mass flow rate, iterations are needed to adjust the flow at each time-step, NITA is a non iterative scheme, so it only works by fixing a constant pressure gradient.

i encountered a reversed flow, but i think it is a numerical error.

I am running now the simulation without NITA, and till now it is working well.

What about your simulation?
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