[tH3f0rC3]

Hi,

does someone know how the courant criterion is used in OpenFoam?
I'm using the chtMultiRegionFoam (transient-version).
Does the solver fit the time step according to the criterion? Thus, the time step isn't constant during the simulation?

Best Regards,
tH3f0rC3

[tH3f0rC3]

I have just recognized that it is possible to set the time step also to delta t = 0.1

Best Regards,
tH3f0rC3

[tH3f0rC3]

Hi,

can I use relaxationFactors for a transient solver like chtMultiRegionFoam?
I have read here that this doesn't work. But I don't understand why?
There is also mentioned that a simpletransient-Solver can work with relaxationFactors. But what is the transientsimple-Solver? Is this solver still calculating a transient case?

Best Regards,
Dirk

[akidess]

Relaxation only applies to the SIMPLE algorithm, whereas most transient solvers in openFoam use PISO. A combination of both algorithms is called PIMPLE in openFoam.

[tH3f0rC3]

Originally Posted by akidess

Relaxation only applies to the SIMPLE algorithm, whereas most transient solvers in openFoam use PISO. A combination of both algorithms is called PIMPLE in openFoam.

Hi,
thanks for your answer.
So can I set up the relaxationFactors in PIMPLE manually? Because you said PIMPLE is a combination of both algorithms.

Best Regards,
tH3f0rC3

[akidess]

Yes, you should be able to specify the relaxation parameters in all SIMPLE and PIMPLE based solvers.

[tH3f0rC3]

Originally Posted by akidess

Yes, you should be able to specify the relaxation parameters in all SIMPLE and PIMPLE based solvers.

Hi,

do you know if this is simply done by typing the following into the fvSolution-file?

relaxationFactors
{
   U   0.7;
   p   0.8;
...
}

Best Regards,
tH3f0rC3