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Re: Problem about 'Residual', 'Drift', 'CFL number'.
Posted: Thu Oct 24, 2019 2:31 pm
by JeremyA
Hello,
I resume this discussion because I am pretty interesting in the answer Yvan
Best regards
Jérémy
Re: Problem about 'Residual', 'Drift', 'CFL number'.
Posted: Tue Dec 17, 2019 3:14 pm
by JeremyA
Up
With Code_Saturne, how can we be sure that the calculation is converged ?
Especially for a transient calculation, which parameter we should check in listing file for convergence of each time step ?
Could you explain each parameter in the listing file : Rhs norm; Norm Residual, Drift, Time residual ?
Thank you
Jeremy
Re: Problem about 'Residual', 'Drift', 'CFL number'.
Posted: Wed Feb 12, 2020 11:36 am
by Ionut G
Hi all!
After some searching on this forum and the functions from code_saturne, I found that norm.residual is the residual I should check in order to see if the simulation is converging or not.
From the file ecrlis.f90, the drift or derive residual is defined as DRIFT=((x_n-x_(n-1) )^2*cell volume)/(time step).
Also from the file ecrlis.f90, the norm residual is defined as norm=sqrt(cs_gres(ncel,volume,w1,w1)),
where cs_gres is the global residual of 2 extensive vectors and is defined as 1/sum(vol) . sum(X.Y/vol)
and w1=((x_n-x_(n-1) )*cell volume)/(time step).
Am I correct? Could someone confirm this?
Best Regards,
Ionut
Re: Problem about 'Residual', 'Drift', 'CFL number'.
Posted: Tue Mar 10, 2020 10:31 pm
by Ionut G
Ionut G wrote: ↑Wed Feb 12, 2020 11:36 am
Hi all!
After some searching on this forum and the functions from code_saturne, I found that
norm.residual is the residual I should check in order to see if the simulation is converging or not.
From the file
ecrlis.f90, the drift or derive residual is defined as
DRIFT=((x_n-x_(n-1) )^2*cell volume)/(time step).
Also from the file
ecrlis.f90, the norm residual is defined as
norm=sqrt(cs_gres(ncel,volume,w1,w1)),
where
cs_gres is the global residual of 2 extensive vectors and is defined as
1/sum(vol) . sum(X.Y/vol)
and
w1=((x_n-x_(n-1) )*cell volume)/(time step).
Am I correct? Could someone confirm this?
Best Regards,
Ionut
Can anyone confirm this? Or, if it is wrong, point me in the right direction?
Thanks in advance,
Ionut
Re: Problem about 'Residual', 'Drift', 'CFL number'.
Posted: Wed Mar 11, 2020 6:33 pm
by Yvan Fournier
Hello,
Yes, this seems correct.
Best regards,
Yvan
Re: Problem about 'Residual', 'Drift', 'CFL number'.
Posted: Wed Mar 11, 2020 6:41 pm
by Ionut G
Thank you very much Yvan!
Best regards,
Ionut