New solver guides
 

Hello,

I have recently put on the wiki two new guides

• scalarTransportFoam: http://openfoamwiki.net/index.php/ScalarTransportFoam
• bubbleFoam: http://openfoamwiki.net/index.php/BubbleFoam

The content of the guides should have gone in the documentation project, and their structure is very similar to the one of the documentation project solvers guide, with the obvious limitations imposed by a wiki compared to LaTeX. Since the documentation project could not work out, I thought to make public the material I was working on.

More will come in some time, with the idea of documenting at least the fundamental main solvers.

Of course comments, tips, and reports on mistakes are welcome!

Best,

Alberto, thanks for adding these new guides to the wiki. In the bubbleFoam description you refer to the phase-intensive formulation of the phase momentum equations proposed by Weller. Do you have a copy of this reference or know where I could get a copy?

The phase intensive formulation has been adopted in Henrik Rusche thesis (you find it on foamcfd.org http://powerlab.fsb.hr/ped/kturbo/Op...chePhD2002.pdf ) and in the paper of Oliveira and Issa cited in the references. If you want the internal report from OpenCFD you should contact them.

The phase-intensive formulation is a way to manage the problem of the singularity in the momentum equation when the phase fraction becomes zero.
If you expand the time derivative and the convective term, so to rewrite the momentum equation in non-conservative form, you can then divide the equation by the phase fraction. In such a situation, you only have one term that could give problems, since the phase fraction has been removed from all the other terms. This term is in the form grad(alpha)/alpha, which is assumed to be well behaved when alpha -> 0. Of course the price you pay is that the momentum equation is resolved in non-conservative form (see the papers from Jeong).

Work is (slowly, it's not my primary activity :D) in progress to have a code with the conservative form of the equations.

Best,

Hi Alberto

Congratulations on making your rather extensive work public. At a first glimpse it looks as an exhaustive description.

Best regards,

Niels

Hi Alberto, thanks a lot for pushing it to the wiki. Especially the part about IOdictionary was very useful to me. And the structure is great if I download in pdf.

Thanks Alberto for your impressive work ! :)

Hi Alberto,

as I wrote you after the launch of The FOAM Documentation Project: Thanks a lot for all the work and effort you have put on documenting these top-level solvers. I think it is really awesome work that really should be made available for the community! :)

That is unfortunatelly true. I think the wiki seems to be one possibility for documentation right now for an indefinite time. I still don't get the result of what happened. And this still gives me a lot food for thought :(

Looking forward to reading more. Again, thanks a lot.

best,
Holger

Hi Holger.

Of course if a more organized project will be created/come back, as I hope, everything I write can be easily re-used/adapted. In the meanwhile, I hope the wiki pages are of some help, especially to new users.

Best,