CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM

gammaEqn.H in the interPhaseChangeFoam solver

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   June 29, 2009, 13:33
Default gammaEqn.H in the interPhaseChangeFoam solver
  #1
Senior Member
 
isabel
Join Date: Apr 2009
Location: Spain
Posts: 171
Rep Power: 8
isabel is on a distinguished road
In gammaEqn.H in the interPhaseChangeFoam we can see this line:

MULES::implicitSolve(oneField(), gamma, phi, phiGamma, Sp, Su, 1, 0);


I know that:
gamma: is the actual value of gamma to be solved
phi: is the normal convective flux
phiGamma: U*gamma + gamma*(1-gamma)*U
1, 0 : max and min gamma values

But I don't unserstand what Sp and Su are. I think that Sp is a source term to solve the equation:

d(gamma)/dt + div(phigamma) = Sp


Am I all right?

What is Su term?

Last edited by isabel; June 30, 2009 at 06:48.
isabel is offline   Reply With Quote

Old   July 7, 2009, 05:01
Default
  #2
Senior Member
 
Sandy Lee
Join Date: Mar 2009
Posts: 207
Rep Power: 9
sandy is on a distinguished road
Quote:
Originally Posted by isabel View Post
In gammaEqn.H in the interPhaseChangeFoam we can see this line:

MULES::implicitSolve(oneField(), gamma, phi, phiGamma, Sp, Su, 1, 0);


I know that:
gamma: is the actual value of gamma to be solved
phi: is the normal convective flux
phiGamma: U*gamma + gamma*(1-gamma)*U
1, 0 : max and min gamma values

But I don't unserstand what Sp and Su are. I think that Sp is a source term to solve the equation:

d(gamma)/dt + div(phigamma) = Sp


Am I all right?

What is Su term?
=================================

Hi, I think, your expression about the gamma equation is right.

In fact, to this equation,
Source term = vDotvAlphal * gamma + (1 - gamma) * vDotcAlphal = (vDotvAlphal - vDotcAlphal) * gamma + vDotcAlphal.

So, Sp = (vDotvAlphal - vDotcAlphal) * gamma , and it will be solved implicitly.
Su = vDotcAlphal, and it is an explicit term in this equation.

But, why Su also includes the term divU*gamma in gammaEqu.H ? If the MULES::implicitSolver was chose, this term should be deleted, right?

Because in MULESTemplates.C, phiPsi = phiGamma = phi*gamma + gamma*(1-gamma)*phi, the term div(phi*gamma) [=divU*gamma ??] has been actually included as follows:

---------------------------
fvScalarMatrix psiConvectionDiffusion
(
fvm::ddt(rho, psi)
+ fv::gaussConvectionScheme<scalar>(mesh, phi, UDs).fvmDiv(phi, psi)
- fvm::Sp(Sp, psi)
- Su
);

surfaceScalarField phiBD = psiConvectionDiffusion.flux();
surfaceScalarField& phiCorr = phiPsi;
phiCorr -= phiBD;

.......
.......

solve
(
psiConvectionDiffusion + fvc::div(lambda*phiCorr),
MULEScontrols.lookup("solver")
);
--------------------------------

Am I right?

Thanks.
sandy is offline   Reply With Quote

Old   July 7, 2009, 13:41
Default
  #3
Senior Member
 
isabel
Join Date: Apr 2009
Location: Spain
Posts: 171
Rep Power: 8
isabel is on a distinguished road
Implicit solver for gamma volumefraction equation
isabel is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Working directory via command line Luiz CFX 4 March 6, 2011 21:02
why the solver reject it? Anyone with experience? bearcat CFX 6 April 28, 2008 14:08
compressible two phase flow in CFX4.4 youngan CFX 0 July 1, 2003 23:32
CFX 5.5 Roued CFX 1 October 2, 2001 16:49
Setting a B.C using UserFortran in 4.3 tokai CFX 10 July 17, 2001 16:25


All times are GMT -4. The time now is 23:13.