FLOW3D scary tactic about VOF
 

Hi foamers
I saw just now on the following link...

https://www.flow3d.com/home/resource...ats-in-a-name/

...that most other CFD software were only using a “Pseudo-VOF methods” and not the real VOF (or truVOF). Cleary they do not grasp the different family trees of VOF. But still, the simulation case shown in this page is interesting. So my question is, has anybody done this simulation in OpenFOAM? If so, could you share the result and case? (I could do this, but I am just swamped in workload for now :().

I think this is a big deal for FLOW3D and I have seen other use this as a justification for using it (phd works).

Cheers
Jon

Hi Jon,

I'm no VoF expert but I did setup a similar case. I had to guess at the size, I guessed at a domain length of 400 mm. Which gives a Re number somewhere near the transition region. Perhaps the domain size should be a factor of 10 smaller.

Depending on the setting you can observe the "incorrect shape". For instance try the case I provided and activate "no-slip" on walls and turn on turbulence.

In the attached picture you can indeed see that the interface is not sharp but there is that expected "flaw". However I wouldn't deem it very disturbed.

Maybe someone else can provide some more interesting thoughts.

The case is meshed with cfMesh. I couldn't attach the case with the mesh since it's to big but you can download it including the mesh here.
And the case files can be downloaded from here:
https://www.dropbox.com/sh/2ec65aqdi...6T1hO5J_a?dl=0



Best Regards

Nicolas

PS. due to the bug at cfd-online I couln't post this sooner.

Thank you for this Nicolas
This is not bad at all :). That is, at least the outcome is not as bad as in the worse case shown with FLOW-3D.

The cfMesh interest me (i.e. the GPL version). Do you know of any manual of this meshing tool as a pdf file?

Cheers
J.

Hi, funny thing. Yesterday I was at the Gothenburg OpenFoam meeting and there was a presentation on isoAdvector, a new scheme which deals with this issue. Have a look here

http://www.cfd-online.com/Forums/ope...culations.html

Yes cfMesh is a really great tool! There's a comprehensive manual included with the source code. It real easy to compile and getting started. Do try it.

Best Regards
Nicolas

Relative to the first post above “different family trees of VOF”…

I just published a paper in which a modified version of the interFoam is used, available for download at:

http://dx.doi.org/10.1016/j.cemconres.2017.02.007

In section 2.2 I talk about the two VOF families, namely the direct methods and the reconstruction methods. So if you need a short intro or references, then here you are.

Unfortunately, I didn’t know about the isoAdvector at the time of writing, so it’s not referred to (will be included in the next paper), but as far as I understand, that method belongs to the reconstruction method.

Cheers
Jon

So what was the conclusion on this? Any further developments/works comparing the Real VOF and Pseudo VOF methods?