Questions about Paraview to show Parallel run of OpenFOAM
 

Dear all:

I run a parallel case, then in the case fold, there are a couple folds named 'processor*' as shown below.

/case
----0
----constant
----system
----processor0
....
----processorN

in this case, how to use paraview to show the results?

I'm new to OpenFoam and Paraview, thanks for your help in advance.

Rds

Jian

I think u should use reconstructPar tool to reconstruct the results, and then use paraFoam!

Hope it helpful!

Thanks for your help~

hello,

You can keep the case decomposed (no recomposePar), and use Paraview: just set the case type as "decomposed" in Paraview.
This will save you time and disk space.

regards,
olivier

Thanks.

Do you mean to cd/case fold/0.1, then use paraFoam?

How to set the case as decomposed? Can you explain in details?

Sorry for my question, I'm new to this tool.

Thanks for your help.

hello,
1) Go to case folder (not the time folder, i.e 01., 0.2 ....).
2) launch Paraview/paraFoam
3) In paraview, set the case to decomposed and Apply.

regards,
olivier

Thanks for your quick reply.

Unfortunely, when I finished 1) and 2), in the paraview, when I select ‘’file ‘---‘open’, then I can't get a proper file to load into paraview.

Is it necessary to use foamToVTK to convert data? When I use foamToVTK in the case fold, it does Not work.

Thanks for your patience.

hello,
NB: I use Paraview, not ParaFoam.
In order to open the case, you must have a dummy file ".foam" inside, like:
your case dir name is "case", then inside case, add an empty file "case.foam", using "touch case.foam" command.
Then when you launch paraview, select the "case.foam" file to open, then you have a case type entry in Paraview / Properties: Reconstructed case OR decomposed.

regards,
olivier

I make it.
Thanks again for your kindness and patience.

Rds

Jian

Thanks for the info!

Will this help to increase performance while post-processing with Paraview?

Dear Olivier

I also want to postprocess my case with decomposed way. I want to know is there a command to run the utility for every processors? For example, If I want to get the Lamda2 variable for each processor, how to do that in a easy way?

Best regards
Ye

hello,
Each OpenFoam tools has the "-parallel" option, so if you stay with a decomposed case, just use like "mpirun -np 8 Lambda2 -parallel" (+ other option if needed).
NB: here, 8 is for a case decomposed in 8 parts.

regards,
olivier

Thank you so much! Olivier

Hi Olivier,

I know this is an old thread so I'm doubtful there's much point posting here but I'm just following up on the instructions you gave for viewing the decomposed case and I'm having trouble making it work.
I tried, from within the case directory itself, NOT the separate processor directories:

touch case2.foam
paraview
Selected decomposed case

This does not work, I get a lot of errors about duplicate entries.

Secondly, I tried this from within the individual processors. Same problem...

Can you please let me know if there's something I'm missing here? Which exact directory should I be in? Should the touch command be done for each processor ? Sorry, I know this might be a silly question but I'm a bit confused

Thanks!
Ariel

Hi,

The steps you have posted should work. You don't need to create a .foam file for the individual processors. It is only for the overall case and by choosing the "Decomposed Case" option, Paraview is usually able to get the case to work.

The duplicated value, I have often encountered mainly with epsilon. I think one solution, is to remove the duplicated entries as it says. Or to not view that particular variable.

Hope this helps.

Cheers,
Antimony

ParaView Parallel reconstruct issue
 

Hi everyone,

I have been modifying the motorBike tutorial to run OpenFoam. After using the "Allrun" script, creating a dummy "foam.foam" file in the main folder and opening as a "decomposed" file in ParaView, I am getting a rebuild issue with artifacts. These artifacts also cause errors when looking through the data. These artifacts are not created when running "paraFoam" in the main folder.

Any assistance would be greatly appreciated and I will provide any information that I can.

PS. I also have a refinement box issue and cannot figure out how to put it in the correct place. You can see it in the picture with the artifacts.

Thank you.

Quick answer: Apply the filter "Merge Blocks".

But do keep in mind that this may require more RAM to process, since it will have almost 2 copies of the same data.

I applied the "Merge Block" filer but I still have artifacts. Instead of blocks, it is the intersection where they merged. So far, I do not have to worry about RAM and have room to install more if needed. Do you have any more advanced processes for me to try?

Maybe there is something I should omit or add to my "Allrun" script? (See below)

Thank you for your suggestions.

Try to turn off the option "Decompose Polyhedra"... more details here: https://openfoamwiki.net/index.php/F...is_in_ParaView

Thank you for your suggestion. I had tried it and it still didn't work so I looked through my settings and found a solution. I had to delete the argument/option for the "reconstructPar" command. Doing so created a folder for all the written iterations form the calculation and created a "perfect" reconstruction in ParaView.

Again, I do appreciate your help.