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

GammaEqn and UEqn in interFoam

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 10, 2007, 11:06
Default Dear all, Could anyone expl
  #1
New Member
 
Brian
Join Date: Mar 2009
Posts: 2
Rep Power: 0
adekian is on a distinguished road
Dear all,

Could anyone explain the following terms in interFoam solver?

1. In gammaEqn.H
What does the third term on the l.h.s of gammaEqn mean?

fvm::div
(-fvc::flux(-phir, scalar(1) - gamma, gammarScheme),
gamma,
gammarScheme)

Is it something like correction term to maintain mass conservation? From what is this term derived?

2. In UEqn.H

What does the term
(fvc::grad(U) & fvc::grad(muf))
on the l.h.s of UEqn account for?

I've been browsing this forum for answers, but so far couldn't find any.

Thank you,

brian
adekian is offline   Reply With Quote

Old   April 11, 2007, 02:03
Default Without fussing about it too m
  #2
Senior Member
 
Hrvoje Jasak
Join Date: Mar 2009
Location: London, England
Posts: 1,763
Rep Power: 21
hjasak will become famous soon enough
Without fussing about it too much:

- in the momentum equation, (fvc::grad(U) & fvc::grad(muf)) is a different formulation of the
div(mu (grad U)^T) term, which does not go away when mu is non-constant

- in the gamma equation the term
(-fvc::flux(-phir, scalar(1) - gamma is an alternative form of the relative velocity term. This is what you get when you reformulate

ddt(gamma) + div(gamma U_gamma) = 0

in the form that will use the volume velocity U instead of phase velocity gamma.

For more details, I would recommend a good Thesis from dr. Henrik Rusche:

@PhdThesis{Rusche:PhD,
author = {Rusche, H.},
title = {Computational fluid dynamics of dispersed two-phase
flows at high phase fractions},
school = {Imperial College, University of London},
year = 2003
}


Hrv
__________________
Hrvoje Jasak
Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk
hjasak 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
About the gammaEqn in interFoam sandy OpenFOAM Running, Solving & CFD 14 March 19, 2014 10:30
Transient interFoam with MRF jaswi OpenFOAM Running, Solving & CFD 18 October 20, 2011 23:29
Nonconservative gammaEqn elisabet OpenFOAM Running, Solving & CFD 20 April 22, 2009 11:50
Possible bug in UEqn for raslescavitatingFoam henry OpenFOAM Bugs 3 November 14, 2008 00:13
InterFoam floooo OpenFOAM Running, Solving & CFD 0 November 3, 2008 12:00


All times are GMT -4. The time now is 18:55.