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

How can I check imbalance?

Register Blogs Community New Posts Updated Threads Search

Like Tree1Likes
  • 1 Post By AliMadayen

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 12, 2014, 17:23
Default How can I check imbalance?
  #1
Senior Member
 
Sangwoo Kim
Join Date: Jul 2014
Location: Seoul, South Korea
Posts: 115
Rep Power: 12
swtbkim is on a distinguished road
Hi all.

I'm simulating about fan.
But result is not reasonable, and I was advised to check imbalance.
He said that I can check imbalance in solver window, i.e. CFX-Solver manager like RMS, Turbulence, and so on.
I searched several manuals, but I couldn't find.

I'm nearly new to CFX, and actually I didn't understand even what imbalance means

Any help will be highly appreciated.
Thanks in advance!
__________________
Best regards
swtbkim is offline   Reply With Quote

Old   October 12, 2014, 19:15
Default
  #2
New Member
 
Ali Madayen
Join Date: Apr 2014
Posts: 22
Rep Power: 12
AliMadayen is on a distinguished road
Hi

When the solver run is finished, the final values for imbalance are reported in the reports shown at the end.
But if you wish to monitor them during thee run, you should add a new monitor for that. Right Click on the upper tabs of the workspace (Like momentum and mass tab) and click on the "New monitor". Ok in the appearing windows, then in the next windows check the boxes for the equations which you want to monitor their imbalance. and click apply. I suggest you to change the monitor axis type to the log scale in the middle tab, cuz you can observe their variation better this way.
Experts should comment on the physical meaning of the imbalance, but as far as I know imbalance means the net difference between boundaries of a domain for each variable. my experience is, an imbalance of 0.1 or less might denote a converged solution.
Best
Ali
ssmacae likes this.
AliMadayen is offline   Reply With Quote

Old   October 18, 2014, 17:32
Default
  #3
Senior Member
 
Sangwoo Kim
Join Date: Jul 2014
Location: Seoul, South Korea
Posts: 115
Rep Power: 12
swtbkim is on a distinguished road
Sorry for my late answer.

Thank you very much. I have checked imbalance near fan.

I'm simulating two fans.
Front fan is OK, but back fan is the problem.
Imbalance of back fan is oscillating in the range of +- 5%.

Do you know about this phenomenon??
I totally don't know what I should do..TAT

Any help will be highly appreciated.
Thank you.
__________________
Best regards
swtbkim is offline   Reply With Quote

Old   October 19, 2014, 06:23
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,852
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Run your simulation for longer to allow it to converge tighter. If it is not converging then refer to this FAQ: http://www.cfd-online.com/Wiki/Ansys...gence_criteria
ghorrocks is offline   Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Problems with mass imbalance kannstmasehn STAR-CCM+ 3 July 26, 2013 04:38
[ICEM] Understanding check mesh output kotimari ANSYS Meshing & Geometry 0 July 15, 2012 09:33
faceZones and topological check mturcios777 OpenFOAM Programming & Development 0 June 15, 2012 14:48
Automated check for convergence Chander CFX 3 May 2, 2012 19:07
Cell check and Boundary check errors AB Siemens 4 October 28, 2004 14:04


All times are GMT -4. The time now is 03:23.