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Old   May 4, 2011, 06:28
Default Coupled Equations ?
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Hi all,
I have 3 equations that are coupled together. First One is the momentum eqn in (U) is stationary no convection (stokes), and the others, one before it (Y) and another after it (C) that are transient convective (contain term fvm::ddt() + fvm::div(Phi, _).

The problem is when using the simpleFoam solver for the implementation i succeeded to converge with 4 relaxation factors being used: 3 for the eqns (U,Y,C) + 1 for pressure.

But my solution is time affected, and whenever i try not to use relaxation factors for (Y,C), it diverges.

I don't really understand the effective or how to use the relaxtion factors for different equations that are coupled together, especially, when some of them are stationary and the others are transient. what to do????????????????

thanks a lot

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