Question about stopat convergence

dferrando · May 9, 2017, 06:06

Hi Foamers.

I'm pretty new in OF and I'm trying some turbulence turorials.
Currently, I'm using simpleFoam with RAS models, and pisoFoam with LES models in te windAroundBuildings tutorial.
My question is: how can i stop the simulation when it converges? And, can i set the convergence criteria?
I would like to set as convergence criteria that the variation of the velocity tends to zero in steady cases (simpleFoam).

Thank you.

piu58 · May 9, 2017, 06:28

This is not so simple. Even with steady solvers you may get an oscillating solution, because the iterations steps will be count as pseudo-timesteps.

I recommend to put a probe (or some probes) at meaningful places in your region and wait for the oscillation frequency gets stable.

dferrando · May 9, 2017, 06:42

Thank you piu.
I'm using probes currently, but my problem is that i don't know how to stop the simulation with expecific criteria.
About probes. Can probes show the velocity magnitude or can they only show the velocity vector?

Thank you.

May 9, 2017, 06:06	Question about stopat convergence	#1
dferrando New Member Diego Ferrando Join Date: Mar 2017 Location: Zaragoza Posts: 19 Rep Power: 9	Hi Foamers. I'm pretty new in OF and I'm trying some turbulence turorials. Currently, I'm using simpleFoam with RAS models, and pisoFoam with LES models in te windAroundBuildings tutorial. My question is: how can i stop the simulation when it converges? And, can i set the convergence criteria? I would like to set as convergence criteria that the variation of the velocity tends to zero in steady cases (simpleFoam). Thank you.

May 9, 2017, 06:28		#2
piu58 Senior Member Uwe Pilz Join Date: Feb 2017 Location: Leipzig, Germany Posts: 744 Rep Power: 15	This is not so simple. Even with steady solvers you may get an oscillating solution, because the iterations steps will be count as pseudo-timesteps. I recommend to put a probe (or some probes) at meaningful places in your region and wait for the oscillation frequency gets stable. __________________ Uwe Pilz -- Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950)

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May 9, 2017, 06:42		#3
dferrando New Member Diego Ferrando Join Date: Mar 2017 Location: Zaragoza Posts: 19 Rep Power: 9	Thank you piu. I'm using probes currently, but my problem is that i don't know how to stop the simulation with expecific criteria. About probes. Can probes show the velocity magnitude or can they only show the velocity vector? Thank you.