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Solving eqation and poor convergence problem

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Old   December 19, 2017, 14:09
Default Solving eqation and poor convergence problem
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behzad Ghasemi
Join Date: Sep 2013
Location: Iran
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Hi dear foamers,

I want to solve magnetic potential equation.
\nabla\cdot(\mu\nabla \phi)=0
I defined this equation like this:
Code:
fvScalarMatrix ksiEqn
(
    fvm::laplacian(interfacePsi.muM() ,ksi)
);
ksiEqn.solve();
Boundary conditions for achieving the uniform vertical magnetic field is:
Code:
inlet
    {
        type            zeroGradient;
    }

    outlet
    {
        type            zeroGradient;
    }

    up
    {
        type            fixedGradient;
        gradient       uniform -1234;
    }

    down
    {
        type            fixedGradient;
        gradient       uniform 1234;
    }

    frontAndBack
    {
        type            empty;
    }
fvSolution dictionary for ksi equation is:
Code:
ksi
    {
        solver           smoothSolver;
        smoother      DICGaussSeidel; //DIC-FDIC-GAMG-diagonal-none
        tolerance      1e-6;
        relTol            0;
    }
When i choose any solver except selected one (smoothSolver) after some time steps courant number rises dramatically and solver diverges. also with mentioned fvSolution setup, solving process is very slow and ksi equtaion iterates 1000 times in every time step!
The log file is attached.
Any suggestion is appreciated.

Thanks in advance,
Behzad
Attached Files
File Type: txt log.txt (153.3 KB, 3 views)
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