CFD Online Discussion Forums - [OpenFOAM] Post Processing Multi Region .OpenFOAM

Hi everybody,

I just started to dive into OpenFOAM' world this week, and I am struggling a bit with these .OpenFOAM files produced while solving planeWall2D case with chtMultiRegionFoam solver.

Set-up: I work on windows 10 Enterprise 64 bits, installed the newest version of Ubuntu (18.04), newest version of OpenFOAM (18.06) following the steps on the OF website, installed Xming to have access to the X server and be able to run paraview from the console (it is thus version 5.4.1 of paraview).

Objective: My objective is to determine the temperature gradient on a 3 phases system (hot fluid running under a thin solid film, topped by cold air).

Before every thing, I would like to say that I went through the OpenFOAM user and beginner guides, some "OpenFOAM for dummies" guides found on the internet, the tutorials from ENSEEIHT, the wiki of OF, asked Google a lot, but could not find an answer to my question until now, which is why I post it here. It might be a stupid question, but I am so new to this world that I might have not found the right words for the search yet.

Step-by-Step: Thus, I started by the usual case cavity, could visualize the results on paraview, and then went through the tutorial on how to add Temperature to icoFoam in order to get a T gradient, which I could visualize in paraview too, but I realized that chtMultiRegionFoam would be much more adapted to my... multi region case.
I ran the planeWall2D case with ./Allrun : everything seems to work well, the .OpemFOAM are being created, but then, I don't understand how to have access to the temperature profiles.
When I try to open these .OpenFOAM files on paraview, it asks me for a compatible reader (which it did not ask me for a .foam file from the cavity case). I choose OpenFOAM, the files appear in the Pipeline Browser, I select the Mesh Regions and click "Apply", then I select all three files and add the Group DataSet filter. But after that, I can not add the "Plot over Line" filter. And I can not choose to display any parameter (p,U, T..), only "Solid Color", "cellNormals", "vtkCompositeIndex", "CasePath" and "vtkBlockColors".

Solutions found:
- I found on this forum that I should maybe "reconstruct" the case (https://www.cfd-online.com/Forums/op...-paraview.html), I tried the option "paraview -builtin" but nothing changed. I am not sure to understand what "reconstruct" means and how it should be done.
- the wiki told me that I should try with "paraFoam -touchAll" and then "paraview" but nothing changed (https://openfoamwiki.net/index.php/H...rocMultiregion).
- renaming the .OpenFOAM files in .foam did not change anything: they open easily in paraview (without the question on the reader) but the problem of the non displayable results stays the same.
- this "echo. > case.foam" command I found there (https://www.cfd-online.com/Forums/op...ndows-7-a.html) would not work: "Command 'echo.' not found, did you mean: command 'echo' from deb coreutils", and when I try with 'echo' instead of 'echo.', nothing changes.
- Using a more recent port for OF on Windows as suggested here (https://www.cfd-online.com/Forums/op...oam-files.html) is the only thing I came accross and did not try yet (maybe because I don't really understand what it means?).

So to summarize, my question is: how to visualize the result of the solving of a multiregion case, issuing .OpenFOAM files.

Thank you very much for having read all the message, and any help is welcome!