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Old   September 3, 2011, 13:41
Default how to improve time step
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I am trying to use SIMPLE algorithm to simulate a 2D flow in micro rectangle pipe. I set up the constant pressure values as inlet and outlet boundary condition and two side is no slip wall. The large scale differences between pressure and size of the pipe leads to the results that it converges only if the step time is very very small(10e-9s). Who could tell me how to do if I want to improve step time to 1s~0.001s?
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Old   September 6, 2011, 22:11
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If you use simpleFoam to deal with an unsteady problem, this is not correct. You should use pisoFoam or pimpleFoam.

If you use pimpleFoam, you can use larger time steps using under-relaxation and outer correctors (under-relaxation is not appropriate in pisoFoam).
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Old   September 7, 2011, 16:00
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Thank you very much , alberto

Do you know where I can find the details about Pimple method? I am programming now by myself and I need make sure every details.

Thank you again.
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Old   September 7, 2011, 21:06
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I am not aware of references about it. You can take a look at pimpleFoam to see how it is implemented.
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