foamMonitor/ residual function: Which residual do I see?

TeresaT · May 10, 2017, 09:55

Hello everyone,
hope someone can help with this:

I use foamMonitor and the residual function to plot my residuals written: (U p), but I don't understand the output, which is one single line für p and two lines for U(Ux and Uy, yeah it's a 2d case).

I am using rhoPimpleFoam with 3 pimple iterations, therefore I have about 17 p residuals. Which one does the residual function write out? And what can I do to get the initial p residual of the last pimple iteration instead?
Writing (U p_12) did not work at all and no p was shown when visualized.

Any Ideas?
Greetings,
Teresa

alexeym · May 11, 2017, 03:19

Hi,

residuals function writes data in write method, which is executed on runTime.write() (i.e. after PIMPLE loop). The function writes values of initial residual.

TeresaT · May 11, 2017, 03:29

Hi aleyeym,

okay thanks! Do you happen to have an idea on how to make it write out all initial residuals (meaning initial residuals of each pimple iteration)?

Greetings,
Teresa

alexeym · May 11, 2017, 03:57

There is no way to do it with residuals function object (and with function object in general, cause no function object methods are executed inside PIMPLE loop).

If I needed this kind of graphs, I would just parse log-file (using Python).

There is foamGraphResUVWP, which creates ASCII tables parsing log-file, though I have never used it.

TeresaT · May 11, 2017, 04:01

Thank you very much alexeym!

I think I will just use foamLog, I think I can manage it that way.

May 10, 2017, 09:55	foamMonitor/ residual function: Which residual do I see?	#1
TeresaT Member Teresa Join Date: Nov 2015 Location: germany Posts: 63 Rep Power: 10	Hello everyone, hope someone can help with this: I use foamMonitor and the residual function to plot my residuals written: (U p), but I don't understand the output, which is one single line für p and two lines for U(Ux and Uy, yeah it's a 2d case). I am using rhoPimpleFoam with 3 pimple iterations, therefore I have about 17 p residuals. Which one does the residual function write out? And what can I do to get the initial p residual of the last pimple iteration instead? Writing (U p_12) did not work at all and no p was shown when visualized. Any Ideas? Greetings, Teresa

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May 11, 2017, 03:19		#2
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38	Hi, residuals function writes data in write method, which is executed on runTime.write() (i.e. after PIMPLE loop). The function writes values of initial residual.

May 11, 2017, 03:29		#3
TeresaT Member Teresa Join Date: Nov 2015 Location: germany Posts: 63 Rep Power: 10	Hi aleyeym, okay thanks! Do you happen to have an idea on how to make it write out all initial residuals (meaning initial residuals of each pimple iteration)? Greetings, Teresa

May 11, 2017, 03:57		#4
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38	There is no way to do it with residuals function object (and with function object in general, cause no function object methods are executed inside PIMPLE loop). If I needed this kind of graphs, I would just parse log-file (using Python). There is foamGraphResUVWP, which creates ASCII tables parsing log-file, though I have never used it.

May 11, 2017, 04:01		#5
TeresaT Member Teresa Join Date: Nov 2015 Location: germany Posts: 63 Rep Power: 10	Thank you very much alexeym! I think I will just use foamLog, I think I can manage it that way.