Residuals : Final or 0 ?
 

Hello

to check convergence in openfoam I used the foamJob & foamLog utilities which write data in text files.

In these text files, for each variable of interest I always have two files :
(example for p)
p_0
pFinalRes_0

Which one should I look at for the convergence?
p_0 seems to decrease continually while pFinalRes_0 has jumps

And what are the meaning of these two residuals?

Thanks for the help

and what about time step continuity error local, global and cumulatice?

How should they behave? Always above 10^-3 or something? Only the last values after X iterations should be looked at?

Thanks for your help

request
 

hi
how can I visualize the residuals? I wonder if there is a way to see the residuals like the fluent?
thanks

you can!

just do like this

solver > log
foamLog log
cd logs
xmgrace -log y -legend load pRes_0

example : simpleFoam log for the solver
(I'm not sure about the name in xmgrace for the variables, just check in the log directory :))

I use http://openfoamwiki.net/index.php/Co...PlotWatcher.py (but I am not neutral)

Hehe, I use pyFoam tools too (and I'm neutral :D)

Best,

help
 

hi foamers
I have simulated a contraction flow. how can I plot for example velocity or the (tauxx-tauxy) across a line connecting two points in the geometry.
after the simulation at every time there are p, phi, U, tau, tau_0 and etc. files at a folder at that time.
thanks a lot

You can plot over lines in paraview. For the stress tensor, you've to first compute it from the fields you stored.

Best,

help
 

hi
thank you very much alberto
but can you possibly explain more? I cant clearly understand your directions
the best

To plot over a line, open you case in paraview, show it as usual, then use the "Plot over a line" filter.

To save the stress tensor, use the stressComponents utility after you run the case.

Best,