CFD Online URL
[Sponsors]
Home > Forums > OpenFOAM

Writing equations

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

Reply
 
LinkBack Thread Tools Display Modes
Old   October 12, 2011, 10:38
Default Writing equations
  #1
Member
 
Join Date: Jun 2011
Posts: 35
Rep Power: 5
mikeP is on a distinguished road
I have a question regarding how the Navier-Stokes is formulated in icoFoam.C file.

fvVectorMatrix UEqn
(
fvm::ddt(U)
+ fvm::div(phi, U)
- fvm::laplacian(nu, U)
);

solve(UEqn == -fvc::grad(p));


Above, all density terms are simplified except the one included in phi (phi = rho x U). How is this possible?

Shouldn't it be something like below:

fvm::ddt(rho, U)
+ fvm::div(phi, U)
- fvm::laplacian(mu, U)
==
- fvc::grad(p)
mikeP is offline   Reply With Quote

Old   October 12, 2011, 12:34
Default
  #2
Senior Member
 
David Gaden
Join Date: Apr 2009
Location: Winnipeg, Canada
Posts: 396
Rep Power: 11
marupio is on a distinguished road
In icoFoam, since density is uniform and constant, it is pulled out of the equation. Even "phi" is actually volume flux.
__________________
~~~
Follow me on twitter @DavidGaden

Last edited by marupio; October 12, 2011 at 12:34. Reason: Even "rho" is... changed to Even "phi" is
marupio 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
Guide: Writing Equations in LaTeX on the CFD Online Forums pete Site Help, Feedback & Discussions 13 December 9, 2014 07:38
CFD governing equations m.gos Main CFD Forum 0 April 30, 2011 15:21
solving only turbulence equations afroz_javed OpenFOAM 1 January 20, 2011 06:25
Question about UDS equations tstorm Fluent UDF and Scheme Programming 1 January 11, 2010 14:04
Linearized Euler Equations a problem with grad ivan_cozza OpenFOAM Running, Solving & CFD 0 October 8, 2008 15:21


All times are GMT -4. The time now is 04:31.