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March 23, 2010, 09:00 |
Residuals : Final or 0 ?
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#1 |
Senior Member
Join Date: Nov 2009
Posts: 111
Rep Power: 16 |
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 |
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April 10, 2010, 17:45 |
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#2 |
Senior Member
Join Date: Nov 2009
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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 |
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April 14, 2010, 14:56 |
request
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#3 |
Member
mohsen kh
Join Date: Nov 2009
Posts: 41
Rep Power: 15 |
hi
how can I visualize the residuals? I wonder if there is a way to see the residuals like the fluent? thanks |
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April 14, 2010, 15:00 |
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#4 |
Senior Member
Join Date: Nov 2009
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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 ) |
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April 14, 2010, 15:15 |
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#5 | |
Assistant Moderator
Bernhard Gschaider
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Quote:
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April 15, 2010, 01:06 |
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#6 |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
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Hehe, I use pyFoam tools too (and I'm neutral )
Best,
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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April 17, 2010, 10:40 |
help
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#7 |
Member
mohsen kh
Join Date: Nov 2009
Posts: 41
Rep Power: 15 |
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 |
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April 17, 2010, 13:38 |
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#8 |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
Rep Power: 36 |
You can plot over lines in paraview. For the stress tensor, you've to first compute it from the fields you stored.
Best,
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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April 18, 2010, 01:17 |
help
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#9 |
Member
mohsen kh
Join Date: Nov 2009
Posts: 41
Rep Power: 15 |
hi
thank you very much alberto but can you possibly explain more? I cant clearly understand your directions the best |
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April 18, 2010, 02:54 |
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#10 |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
Rep Power: 36 |
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,
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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