CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Main CFD Forum

Implementation of BC's in FV code

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 31, 2008, 18:38
Default Implementation of BC's in FV code
  #1
alex
Guest
 
Posts: n/a
Hi there,

Im not sure how to implement boundary conditions in a finite volume method.

This is what I have so far:

Discretized transport equation (pure convection) is of the form

ap*phi_P -aw*phi_W -ae*phi_E = S

and aP=aE+aW

I'm using upwind for face values ( and U is positive) so aE=0 On a boundary, I set the coefficient of the boundary face to zero and add the flux to the source term. So on the west boundary, aW is set to zero and the source term is nonzero. However, this will make aP=(aW+aE)=0 so the TDMA solver will not converge.

Any help greatly appreciated

Thanks!
  Reply With Quote

Old   March 31, 2008, 20:00
Default Re: Implementation of BC's in FV code
  #2
Ananda Himansu
Guest
 
Posts: n/a
At the west boundary, calculate aW (non-zero) by the usual method (from the prescribed flux, likely). Set aP=(aW+aE) = aW+0 = aW. Next, set aW to zero (without changing aP), and add the prescribed flux to the source term S (making the latter non-zero). Solve using the TDMA. Allow to cool, stir, and enjoy.
  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
Editing code Joseph Main CFD Forum 0 May 28, 2007 16:18
What is the Better Way to Do CFD? John C. Chien Main CFD Forum 54 April 23, 2001 08:10
Pseudo compressibility implementation free code vijay pargaonkar Main CFD Forum 0 March 18, 2001 02:49
own Code vs. commercial code Bernhard Mueck Main CFD Forum 10 February 16, 2000 11:07
Use of an hydrodynamic model integrated in the vertical by the PHOENICS code Hafsia Zouhaier Main CFD Forum 2 March 15, 1999 09:23


All times are GMT -4. The time now is 15:51.