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Old   February 12, 2013, 05:10
Default Convergence/Residuals Ending
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Vasileios Sassanis
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Is there any way to stop automatically the solution when our variables reach convergence?

For example, given only your dT and not endTime, the solution stops when it reaches convergence.

Thanks
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Old   February 12, 2013, 05:19
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Marco Longhitano
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Hi,

you can add to your fvSolution file the following lines;

Quote:
SIMPLE
{
nNonOrthogonalCorrectors 0;

residualControl
{
p 1e-5;
U 1e-5;
"(k|epsilon|omega)" 1e-7;
}
}
So, it will stop once reach the written tolerance!

Regards
Marco
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Old   February 12, 2013, 05:53
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Thanks man!
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Old   March 4, 2013, 11:41
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Vasileios Sassanis
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Marco,

i had problems in controlling the residuals using icoFoam. I added the lines you suggested but nothing happens.

solvers
{
p
{
solver PCG;
preconditioner DIC;
tolerance 1e-04;
relTol 0;
}

U
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-05;
relTol 0;
}
}

PISO
{
nCorrectors 2;
nNonOrthogonalCorrectors 0;
pRefCell 0;
pRefValue 0;

residualControl
{
p 1e-3;
U 1e-3;
}
}

I put 1e-03 to check the case and i plot initial residuals on-the-fly. Both u and p pass this limit but the solution continues, it doesn't stop.

(I use OpenFoam 2.1.1)
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Old   March 4, 2013, 11:47
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Marco Longhitano
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Hi,

do you wanna simulate a steady or a transient simulation?
icoFoam solver is inherently transient! So it does not make sense to stop the solution to a steady state!

Regards
Marco
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Old   March 4, 2013, 12:42
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I'm studying the flow over a sphere using icoFoam, which has a transient part 'till the distribution around the sphere reaches a "steady-state", meaning it doesn't change no matter how much time passes from there on.

So, now that i know that ,when my initial residuals have reached e.g. 1e-05 for p, my solution has converged and i don't need to have it running any more, i want it to stop automatically when reaching this values.

Thanks for all your replies,really
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Old   June 3, 2014, 05:53
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Mehrez
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Quote:
Originally Posted by VSass View Post
I'm studying the flow over a sphere using icoFoam, which has a transient part 'till the distribution around the sphere reaches a "steady-state", meaning it doesn't change no matter how much time passes from there on.

So, now that i know that ,when my initial residuals have reached e.g. 1e-05 for p, my solution has converged and i don't need to have it running any more, i want it to stop automatically when reaching this values.

Thanks for all your replies,really
Hi dear VSass,
Did you solve your problem ?
I'm trying to do the same thing.
Thank you
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Old   June 14, 2014, 04:48
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Vasileios Sassanis
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Hello Mehrez,

as said above you should add the following lines in fvSolution.

residualControl
{
p 1e-06;
U 1e-06;
}

However, I would recommend this approach only in cases where you know for sure that the flow field is fully developed and no other alteration is going to occur. This comes with experience.

Kind regards
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