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-   -   Large time Step Continuity Errors (http://www.cfd-online.com/Forums/openfoam-solving/80572-large-time-step-continuity-errors.html)

ozzythewise September 29, 2010 20:51

Large time Step Continuity Errors
 
Hello all,

I'm trying to do a simulation using simpleFoam, turbulent model komega and trying to use an upwind discretisation scheme. When I run it, I get the follow outputs:


Time = 1000

DILUPBiCG: Solving for Ux, Initial residual = 0.0531176, Final residual = 4.97151e-08, No Iterations 3
DILUPBiCG: Solving for Uy, Initial residual = 0.0524418, Final residual = 2.62207e-08, No Iterations 3
DICPCG: Solving for p, Initial residual = 0.378508, Final residual = 7.74833e-08, No Iterations 182
time step continuity errors : sum local = 8.80457e+47, global = -2.78683e+45, cumulative = -4.87884e+45
DILUPBiCG: Solving for omega, Initial residual = 0.0812003, Final residual = 5.90716e-08, No Iterations 3
DILUPBiCG: Solving for k, Initial residual = 0.145069, Final residual = 1.30273e-09, No Iterations 4


As you can see, my time step continuity errors are enormous. I think the issue is in my fvschemes file, but I can't seem to find where. Here is my fvschemes file:

ddtSchemes
{
default steadyState;
}

interpolationSchemes
{
default upwind phi;
}

gradSchemes
{
default Gauss upwind phi;
}

divSchemes
{
default Gauss upwind phi;
}

laplacianSchemes
{
default Gauss upwind phi corrected;
}


snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
p ;
U;
}

If anyone has any suggestions that'd be awesome, I really need some help with this one.

Thanks
-J

ozzythewise September 29, 2010 20:55

Additional info: When I use a central differencing scheme, the solution is stable. However, I need to use upwind, so I'm not sure what's going on here.

THanks again


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