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

One question about the discretization of governing equation in OpenFOAM

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 14, 2011, 22:05
Default One question about the discretization of governing equation in OpenFOAM
  #1
Member
 
Jinbiao Xiong
Join Date: Oct 2009
Location: China/Japan
Posts: 50
Rep Power: 7
JinBiao is on a distinguished road
Send a message via MSN to JinBiao
I found there is an extra term in some solvers. I am not sure about the reason. For example in the TEqn.H of buoyantBoussinesqSimpleFoam. The scalar matrix is constructed via

fvScalarMatrix TEqn
(
fvm::div(phi, T)
- fvm::Sp(fvc::div(phi), T)
- fvm::laplacian(kappaEff, T)
);

The second term seems not necessary here. And it also make the discretization become nonconservative. I wonder why this is necessary. In contrast in the UEqn.H in the same solver

tmp<fvVectorMatrix> UEqn
(
fvm::div(phi, U)
+ turbulence->divDevReff(U)
);

Such term does not appear. Can anyone explain why we need this?

Thanks a lot.

Best Regards,
__________________
Jinbiao
JinBiao is offline   Reply With Quote

Old   December 30, 2011, 04:49
Default
  #2
Senior Member
 
Tarak
Join Date: Aug 2010
Location: State College, PA
Posts: 105
Rep Power: 6
Tarak is on a distinguished road
Hii,

The line is added to have values of T bounded in the algorithms like SIMPLE where we have partial convergence of pressure. Check this: origin of fvm::Sp(fvc::div(phi_), epsilon_) in kepsilon Eqn?
Tarak 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
New OpenFOAM Forum Structure jola OpenFOAM 2 October 19, 2011 06:55
Cross-compiling OpenFOAM 1.7.0 on Linux for Windows 32 and 64bits with Mingw-w64 wyldckat OpenFOAM Announcements from Other Sources 3 September 8, 2010 06:25
Convergence question with regards to discretization karananand Main CFD Forum 0 July 16, 2010 00:27
Modified OpenFOAM Forum Structure and New Mailing-List pete Site News & Announcements 0 June 29, 2009 05:56
UDF to add two governing equation?? T.K. Yang FLUENT 0 May 9, 2006 02:54


All times are GMT -4. The time now is 21:49.