CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM (http://www.cfd-online.com/Forums/openfoam/)
-   -   bubbleFoam (http://www.cfd-online.com/Forums/openfoam/68611-bubblefoam.html)

 rans2009 September 25, 2009 09:02

bubbleFoam

Hi friends,
I am here again with some silly doubts,
I was solving bubbleFoam tutorial after I got stuck with my model (also using bubbleFoam), I wanted to know how the volume fraction of water is defined inside the domain, well volume fraction of bubble(gas) is define using alpha term, but howz water volume fraction defined.

Sameera

 bigred September 28, 2009 03:43

I thought that the alpha is the combined water and gas fraction. So, if alpha is 1, then there is only water, if it is 0 then there is only gas, if it was 0.5 then there would be 50% water and 50% gas.

 rans2009 October 1, 2009 06:37

Thanks Matthew,
I came to know the idea behind this and alpha represents volume fraction of gas and beta gives fraction of water,

thank you

 rans2009 October 5, 2009 04:28

/* fvScalarMatrix betaEqn
(
fvm::ddt(beta)
+ fvm::div(phi, beta, scheme)
+ fvm::div(-fvc::flux(phir, scalar(1) - beta, scheme), beta, scheme)
);
betaEqn.relax();
betaEqn.solve();

alpha = 0.5*(scalar(1) + sqr(scalar(1) - beta) - sqr(scalar(1) - alpha));
*/

Hi friends I am again asking questions about volume fractions in bubleColumn tutorial,
1) whats this beta equation,
2) is it volume intialzation file of water or other fluid???,
3) Whats the equation in block font represent is it correction factor for alpha ?

Can anyone explain me this doubt thanks in advance