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Old   February 2, 2005, 08:14
Default Hi, I'm wondering how one ca
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Marco Kupiainen (Kupiainen)
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Hi,
I'm wondering how one can solve systems of equations in OpenFOAM. I am not interested in a segregated solver of the PISO, SIMLE type, since I have source terms.
Does one have to construct a vector containing the unknowns, e.g. U=(rho, rho*u, rho*v, rho*w, rho*E) for the NS-equations. And then do the time integration with some scheme, e.g. Runge-Kutta or similar. Will there be problems with the physical units? What about the operators, div, grad, etc. can they handle this?
What other difficulties can you foresee? Is this a feasible way at all with OpenFOAM?
best regards
Marco
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Old   February 2, 2005, 13:28
Default Why cant you use a segregated
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Eugene de Villiers (Eugene)
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Why cant you use a segregated solver with source terms like the rest of us? OpenFOAM does not at present incorporate a block solver, so you are limited to a segregated approach.

To see how equations are defined and solved, please look at any solver's top level code, e.g. RANS based incompressible solver, OpenFOAM-1.0.2/applications/solvers/incompressible/turbFoam/turbFoam.C
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Old   February 2, 2005, 13:31
Default For this case, the segregated
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Hrvoje Jasak (Hjasak)
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For this case, the segregated solver is not appropriate - you get killed in cross-equation coupling because source-coupling is very strong. We basically need a block solver and the sooner the better.

If you try to solve this segregated, you will end up violating the entrophy condition because of lagged source interaction.

Hrv
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Old   February 2, 2005, 13:55
Default We have very successful segre
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Henry Weller (Henry)
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We have very successful segregated solvers for this kind of problem, it's just a matter of choosing the best variables to solve for and being consistent with the discretisation and boundary conditions.
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