
[Sponsors] 
Source term in the compressible momentum equation 

LinkBack  Thread Tools  Search this Thread  Display Modes 
April 9, 2015, 17:13 
Source term in the compressible momentum equation

#1 
New Member
Daniel Duque
Join Date: Jan 2011
Location: ETSIN, Madrid
Posts: 28
Rep Power: 14 
Hello everyone.
I'm studying this piece of code for the source term in the momentum equation. It's a laminar, compressible simulation in which mu is NOT constant. Code:
tmp<fvVectorMatrix> laminar::divDevRhoReff(volVectorField& U) const { return (  fvm::laplacian(muEff(), U)  fvc::div(muEff()*dev2(T(fvc::grad(U)))) ); } Laplacian( mu U) + div ( mu ( gradU^t  (2/3) divU I ) ) If mu was constant I would be happy, even if the second term is mathematically equal to (1/3) grad divU. There is surely some reason to write it this way. But I am concerned with the first term, which should be: div ( mu gradU) Perhaps that's what fvm::laplacian(muEff(), U) is ?? (It could also be mu Laplacian U, which wouldn't be good.) Btw, it seems the fluid is supposed to be Stokesian, so that lamba+(2/3) mu =0, am I right? Thanks! Daniel 

April 9, 2015, 17:33 

#2 
Member
ali alkebsi
Join Date: Jan 2012
Location: Strasbourg, France
Posts: 82
Rep Power: 13 

April 10, 2015, 04:58 

#3 
New Member
Daniel Duque
Join Date: Jan 2011
Location: ETSIN, Madrid
Posts: 28
Rep Power: 14 

Tags 
compressible flow, laplacian operator, momentum equation, momentum source, navierstokes solver 
Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Source Term due to evaporation in energy transport equation  styleworker  OpenFOAM Programming & Development  3  September 7, 2022 03:09 
what is swap4foam ??  AB08  OpenFOAM  28  February 2, 2016 01:22 
[swak4Foam] swak4foam building problem  GGerber  OpenFOAM Community Contributions  54  April 24, 2015 16:02 
UDF for source term in momentum equation  Enrico  FLUENT  9  May 30, 2014 11:34 
Adding a momentum source term  segersson  OpenFOAM Running, Solving & CFD  5  March 2, 2006 23:06 