bubbleFoam

rans2009 · September 25, 2009, 10:02

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.

can anyone help me about this doubt,

thanks in advance,
Sameera

bigred · September 28, 2009, 04:43

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, 07:37

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, 05:28

/* 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

Anticipating for your kind reply,
Sameera

September 25, 2009, 10:02	bubbleFoam	#1
rans2009 New Member Sameera Join Date: Sep 2009 Posts: 15 Rep Power: 17	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. can anyone help me about this doubt, thanks in advance, Sameera

September 28, 2009, 04:43		#2
bigred New Member Matthew Philpott Join Date: Aug 2009 Location: Belgium Posts: 24 Rep Power: 17	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. __________________ CAELinux 2009 + OF1.5 Ubuntu 9.04 x64 (jaunty jackalope) + OF1.6

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October 1, 2009, 07:37		#3
rans2009 New Member Sameera Join Date: Sep 2009 Posts: 15 Rep Power: 17	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

October 5, 2009, 05:28		#4
rans2009 New Member Sameera Join Date: Sep 2009 Posts: 15 Rep Power: 17	/* 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 Anticipating for your kind reply, Sameera