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cfdfans March 25, 2010 23:16

Momentum equation of interFoam?
Dear Foamer,
I am a beginner in interFoam of OpenFoam. I wonder if there are someone could show me how the momentum equation of interFoam in version 1.6.x is demonstrated below:

ddt(rho,U) + div(rhophi,U) = grad(P) + rho*g + fv + laplace(mueff,U)

fv : surface tension force
rho = alpha1*rho1+(1-alpha1)*rho2
U = alpha1*U1+(1-alpha1)*U
rhophi = rho*U + alpha1*(1-alpha1)*(rho1-rho2)*(U1-U2)

I tried from two equations of each phase, but I am not successful.

Thanks a lot.


idrama March 26, 2010 07:58

Check the internet for Ruschke's Ph. D. Thesis!

In this forum is this thesis serveral times mentioned, just keep looking at it.

If ya can't find it, send me aderess to where I can send it!


idrama March 26, 2010 09:14


cfdfans March 26, 2010 12:14

Thanks for your quick reply.
In fact, I had read Rusche's PhD thesis several times but if I wouldn't make a mistakes and what I understand is that the chapter 3: Two Fluid Methodology describes the averaged equation for each phase and the model for the last term in the averaged momentum equation; and the chapter 4: Interface capturing Methodology talks about the mometum equation for a domaine with an interface by using the indicator gamma or alpha1.
By looking all two chapters, I could not find some things similar to:
and how can we explain that:
rhophi = rho*U + alpha1*(1-alpha1)*(rho1-rho2)*(U1-U2)

Thanks for your answer.


idrama March 28, 2010 04:17

Properly you have already found it:

In this blog there is a hot discussion on going.


cfdfans March 28, 2010 07:54

Dear Claus Meister,
Thanks for your indication on VOF method blog. I will go to these comments on the blog immediately.
Best regards

cfdfans March 28, 2010 08:46

Dear Claus,
I read the blog of VOF method, really, there are many comment on VOF method, especially on the gamma equation, on interface properties base on gamme discusion, on MULES...
And I found that there are the thesis of Patricio Bohorquez is very interesting, especially the definition of "mass velocity" and "volumetric velocity". But I could not find out my question there.
Thanks for your patient support.
Best regards.

einatlev September 13, 2012 15:27

see equation 4.24 in Rusche's thesis. That's the form of the momentum equation closest to the code as far as I could find.

hossein_y62 January 4, 2013 05:44


Originally Posted by idrama (Post 251824)

Hi idrama,
Would yo please send me the PDF file of this thesis, I cannot access to it.

nimasam January 5, 2013 04:09

you can also check this journal:

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