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

Divergence detected in AMG solver:Temperature

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

Reply
 
LinkBack Thread Tools Display Modes
Old   May 3, 2012, 08:43
Default Divergence detected in AMG solver:Temperature
  #1
New Member
 
Yogesh Patil
Join Date: Nov 2009
Posts: 20
Rep Power: 7
foamcfd is on a distinguished road
Hi All,
I am getting an error:divergence detected in AMG solver:temperature. Residual for energy is fine (below 1E-06). However monitored temperature is oscillating and diverges. What can be the reason for this and how can I solve this?
I changed energy cycle type to F with BCGSTAB and double precision but no convergence.
Using coupled solver would not result in divergence. However monitored temperature would oscillate in 3 deg band. I would prefer avoid this oscillation so tried with low energy URF(0.85) but no success. Also I would avoind using coupled solver because of the hardware constraints.

Any suggestions to get solution with segregatted solver?

Many Thanks
foamcfd is offline   Reply With Quote

Old   May 3, 2012, 10:48
Default
  #2
Senior Member
 
Lucky Tran
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 605
Rep Power: 12
LuckyTran is on a distinguished road
Quote:
Originally Posted by foamcfd View Post
Also I would avoind using coupled solver because of the hardware constraints.

Any suggestions to get solution with segregatted solver?
Go ahead and use it. It's as simple as a click of a button. Any reason why you're not already using it? There are no visionaries here, we cannot know beforehand why you are doing anything a certain way. Please give some details about your simulation if you want any fruitful discussion.
LuckyTran is offline   Reply With Quote

Old   May 4, 2012, 03:25
Default
  #3
New Member
 
Yogesh Patil
Join Date: Nov 2009
Posts: 20
Rep Power: 7
foamcfd is on a distinguished road
Hi,
Here is the problem description. This is basically natural convection problem of pipe flow and water jacket around it. Temperature of fluid inside pipe is around 120 degC and water is at 25degC. Water jacket is insulated from outside and so is the open area of pipe. I need to analyse this system first in steady state to get the temperature and flow field. Then carry out unsteady state analysis to see how much time does it take to reach a specified value of temperature at a specified location inside the pipe.
While running for the steady state analysis I am getting the dievergence error as explained in the last post.

Thanks,
foamcfd is offline   Reply With Quote

Old   May 4, 2012, 12:23
Default
  #4
Senior Member
 
Lucky Tran
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 605
Rep Power: 12
LuckyTran is on a distinguished road
Quote:
Originally Posted by foamcfd View Post
This is basically natural convection problem of pipe flow and water jacket around it.
Segregated solver will work. It will just take more iterations than the coupled solver (but it's faster too so that should make up for it).
LuckyTran 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
Divergence detected in AMG solver: ads-0 Patrino FLUENT 4 April 18, 2014 01:53
Divergence detected in AMG Solver:TEMPERATURE Sachin Nimbalkar FLUENT 14 March 4, 2013 19:53
Quarter Burner mesh with periosic condition SamCanuck FLUENT 2 August 31, 2011 11:34
user subroutine error CFDUSER CFX 2 December 9, 2006 07:31
user defined function cfduser CFX 0 April 29, 2006 10:58


All times are GMT -4. The time now is 18:57.