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How can I convert a steady state solver to a transient state solver? (time-dependent)

Dear All

I am working on PEM fuel cell modeling in OpenFOAM. I need to do a simulation for the transient state. How can I convert a steady-state solver to a transient state solver? (time-dependent). For steady-state code is running with no error. Any suggestion for it?

Thank you,

Ramakant Gadhewal

Research Scholar

Chemical Engg

NIT Warangal


OpenFOAM 13-05-21, 12:52 p.m. ramakantgadhewal
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Dear Ramakant,

Change of solver would require the changes in two major files in OpenFOAM: the fvSchemes file & the fvSolutions file. Could you be more specific regarding the solver which you're planning on modifying?

Regards,
Ashley
13-05-21, 1:09 p.m. ashleymelvin


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Dear Ashley I am working on pemfcSinglePhaseNonIsothermal.
13-05-21, 2:11 p.m. ramakantgadhewal

Dear Ramkant,

Currently, which steady-state OpenFOAM solver are you planning on modifying?

Regards,
Ashley


14-05-21, 3:29 p.m. ashleymelvin

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Dear Ashley I am working on pemfcSinglePhaseNonIsothermal.
14-05-21, 9:30 p.m. ramakantgadhewal

Dear Ramkant,

Since the solver you have mentioned is not a standard solver, but a custom one, I can't really comment on the specific changes that needs to be made. I can probably give you an idea of how it could be done using the example of icoFoam (transient, incompressible) & simpleFoam (steady, incompressible). If you can compare the fvSchemes of the two solvers, you find that the ddtSchemes for transient simulation has been mentioned as Euler in icoFoam while the same for simpleFoam is steadyState. There would be some more changes in the schemes depending on the loop you'll be using. Since most steady-state solvers use the SIMPLE (or at times SIMPLEC) loop, you'll need to have that converted to PISO or PIMPLE in your case (in the source code). This would also require change(s) in the fvSolutions file as the solution convergence parameters specified in it is dependent on the loop that the source code uses.

I understand that the steps I have mentioned are generic & again, because this is a custom solver, specifying the exact changes would be difficult. I hope it gives you an idea on how to proceed.

Regards,
Ashley


24-05-21, 3:23 p.m. ashleymelvin

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Dear Ashley Thank you very much for your deep explanation of steady and transient solver. I will look into these algorithms and try to adopt the methodology of the solvers. Thank you for your time. Regards Ramakant Research scholar Chemical Engg NIT Warangal
24-05-21, 7:35 p.m. ramakantgadhewal


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