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

Restarted run and change in geometry...question

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

Reply
 
LinkBack Thread Tools Display Modes
Old   August 25, 2006, 11:20
Default Restarted run and change in geometry...question
  #1
Vanessa
Guest
 
Posts: n/a
Dear all,

I had been running a problem with a certain geometry (short elastic pipe) and the first results are really difficult to get because of very complex boundary conditions. I changed my geometry (larger pipe with same diameter) and I used the result file (.res) of a previous run with a much shorter pipe as the input condition for a restarted run with my new geometry. I didn't have any problem whatsoever but I was wondering what is CFX doing with the flow variables...it is not very clear to me. My concrete question is: if my restarted simulation is running long enough, I should get appropriate results for my new pipe...or am I wrong? In any case, the initialization of my problem is extremely complicated and I am not getting results at all with a "normal" initialization...that's why I decided to use the results of a previous run (even for a much shorter pipe) as "initial guess".

Any help on this subject would be highly appreciated.

Cheers,

Vanessa

  Reply With Quote

Old   August 25, 2006, 16:22
Default Re: Restarted run and change in geometry...questio
  #2
alex
Guest
 
Posts: n/a
hi vanes'! as far as i am concerned, you could interpolate the results of your first run on the second mesh (larger pipe with the same diameter. as a consequence u are going to obtain a good initialisation and your second run will converge quikly.

Alex
  Reply With Quote

Old   August 26, 2006, 09:48
Default Re: Restarted run and change in geometry...questio
  #3
Joe
Guest
 
Posts: n/a
If you are running a steady state problem a properly converged solution should be independant of your initial guess. So you are free to use any sort of initial condition if it will help you attain convergence. However you must make sure your solution converges properly.
  Reply With Quote

Old   August 28, 2006, 07:55
Default Re: Restarted run and change in geometry...questio
  #4
Robin
Guest
 
Posts: n/a
"If you are running a steady state problem a properly converged solution should be independant of your initial guess."

This is not strictly correct. Although it is not entirely common, it is possible to create a model which has multiple stable states. The initial guess will determine which state the solution ends up in.

-Robin
  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
how to change run directory camoesas OpenFOAM 4 July 7, 2013 06:28
Change parameter and run cases parallel lingdeer ANSYS 0 July 29, 2011 10:27
change fixedGradient BC during run fisch OpenFOAM 4 June 8, 2011 12:34
geometry change in snappychtMultiRegion tutorial jofry OpenFOAM 1 October 28, 2010 09:59
Change BC during the run? jx FLUENT 7 November 6, 2003 21:45


All times are GMT -4. The time now is 19:22.