|
[Sponsors] |
Hi,I have a question about momentum equation in interFoam |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
January 11, 2013, 10:19 |
Hi,I have a question about momentum equation in interFoam
|
#1 |
New Member
anonymous
Join Date: Apr 2010
Posts: 14
Rep Power: 15 |
Dear Foamers:
I have read Henrik Rusche's phd thesis.Now i meet a question in the momentum equation of interFoam. Mr. Rusche defined an 'H' operator AH=As-An*phi where 'As' means source vector.Does As include the item like -grad(p)-g*x*grad(rho)...?Or What included in As?Thank you very much! |
|
January 13, 2013, 06:59 |
|
#2 |
Senior Member
Fumiya Nozaki
Join Date: Jun 2010
Location: Yokohama, Japan
Posts: 266
Blog Entries: 1
Rep Power: 18 |
Take a look at the interFoam/UEqn.H:
Code:
fvVectorMatrix UEqn ( fvm::ddt(rho, U) + fvm::div(rhoPhi, U) + turbulence->divDevRhoReff(rho, U) == sources(rho, U) ); fvVectorMatrix UEqn. In the above definition of UEqn, there is no terms corresponding to grad(p) and g*x*grad(rho), so these terms are not included in the H operator in the interFoam solver. Fumiya |
|
January 14, 2013, 08:47 |
|
#3 |
New Member
anonymous
Join Date: Apr 2010
Posts: 14
Rep Power: 15 |
Here's the UEqn.H in of 2.1.1
surfaceScalarField muEff ( "muEff", twoPhaseProperties.muf() + fvc::interpolate(rho*turbulence->nut()) ); fvVectorMatrix UEqn ( fvm::ddt(rho, U) + fvm::div(rhoPhi, U) - fvm::laplacian(muEff, U) - (fvc::grad(U) & fvc::grad(muEff)) //- fvc::div(muEff*(fvc::interpolate(dev(fvc::grad(U)) ) & mesh.Sf())) ); UEqn.relax(); if (pimple.momentumPredictor()) { solve ( UEqn == fvc::reconstruct ( ( fvc::interpolate(interface.sigmaK())*fvc::snGrad(a lpha1) - ghf*fvc::snGrad(rho) - fvc::snGrad(p_rgh) ) * mesh.magSf() ) ); } The H operator is constructed by : fvVectorMatrix UEqn ( fvm::ddt(rho, U) + fvm::div(rhoPhi, U) - fvm::laplacian(muEff, U) - (fvc::grad(U) & fvc::grad(muEff)) //- fvc::div(muEff*(fvc::interpolate(dev(fvc::grad(U)) ) & mesh.Sf())) ); Right? |
|
January 28, 2013, 22:27 |
|
#5 |
Senior Member
Santiago Marquez Damian
Join Date: Aug 2009
Location: Santa Fe, Santa Fe, Argentina
Posts: 452
Rep Power: 23 |
Hi, the H operator gives which is defined in Hrv thesis for the implicit terms used in the fvVectorMatrix declaration.
Regards.
__________________
Santiago MÁRQUEZ DAMIÁN, Ph.D. Research Scientist Research Center for Computational Methods (CIMEC) - CONICET/UNL Tel: 54-342-4511594 Int. 7032 Colectora Ruta Nac. 168 / Paraje El Pozo (3000) Santa Fe - Argentina. http://www.cimec.org.ar |
|
November 13, 2017, 12:05 |
|
#6 | |
Member
behzad Ghasemi
Join Date: Sep 2013
Location: Iran
Posts: 56
Rep Power: 12 |
Quote:
I've a question about momentum equation of interFoam. why Area (mesh.magSf()) is multiplied to RHS of equation? |
||
December 18, 2017, 18:34 |
|
#7 |
Super Moderator
Tobias Holzmann
Join Date: Oct 2010
Location: Tussenhausen
Posts: 2,705
Blog Entries: 6
Rep Power: 51 |
This is based on the divergence operator. We interpolate the deviatoric part of grad(U) to the face and have to multiply it with the surface normal vector (area of the face). As it is given in Hrv thesis, the divergence is approximately the sum of fluxes through the faces.
__________________
Keep foaming, Tobias Holzmann |
|
December 18, 2017, 18:40 |
|
#8 | |
Member
behzad Ghasemi
Join Date: Sep 2013
Location: Iran
Posts: 56
Rep Power: 12 |
Quote:
Regards, |
||
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
solving the momentum equation in UEqn. | callahance | OpenFOAM | 2 | October 18, 2012 10:38 |
momentum equation question | mauz | Main CFD Forum | 0 | March 26, 2010 12:34 |
Momentum equation used by mixture model | George | FLUENT | 0 | May 19, 2005 14:07 |
Problem with momentum equation | Francisco | Main CFD Forum | 4 | August 5, 2004 21:04 |
Nonstaggered Grids and Momentum Interpolations | S. Wang | Main CFD Forum | 3 | March 2, 2001 14:44 |