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

Problems with SUPG body force term

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

Reply
 
LinkBack Thread Tools Display Modes
Old   January 21, 2006, 18:51
Default Problems with SUPG body force term
  #1
FEM question
Guest
 
Posts: n/a
Dear friends,

I have been getting problems with the SUPG term of the body forces (BF) in a program I'm implementing. I have a SUPG/PSPG finite element incompressible Navier-Stokes program where every time I "turn on" the evaluation of the SUPG term of the body force the program blows up. This problem doesn't happen when I use only the Galerkin term and the result seems to be ok. I know that the SUPG term of the forcing terms introduces more non-linearity in the problem, so, my body forces evaluation is before the predictor-multicorrector loop and are linearized with the time lagged velocity field. So, what could be wrong? My SUPG BF vector is defined by:

f_SUPG = int[ tau_SUPG * (u grad w) * f]

int = integral operator grad = gradient operator tau_SUPG = stabilization parameter u = velocity vector (lagged in time for linearization purposes) w = weighting function f = force vector

being f and w defined by:

f = sum(N_a*f_a) and w = sum(N_b*c_b)

would reach:

f_SUPG = tau_SUPG*{int[u*grad*N_a*N_b]*f}*c_b

could anybody give me a hand to solve it?

thanks

FEM

  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
Force can not converge colopolo CFX 13 October 4, 2011 22:03
ATTENTION! Reliability problems in CFX 5.7 Joseph CFX 14 April 20, 2010 15:45
HOW TO GIVE BODY HEAT GENERATION TERM NITUL KALITA FLUENT 3 December 18, 2008 12:23
DPM Body Force Sandilya Garimella FLUENT 1 April 8, 2008 03:30
Large varying body force vs. Rhie-chow correction john Main CFD Forum 1 May 23, 2007 02:27


All times are GMT -4. The time now is 11:35.