CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

Rookiequestions error solution singularity etc

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 31, 2006, 10:28
Default Hey. I have a few simple(?)
  #1
ham
Member
 
Marcus Hammar
Join Date: Mar 2009
Posts: 33
Rep Power: 17
ham is on a distinguished road
Hey.

I have a few simple(?) questions.

First let me describe my situation:
I have a (2m*2m) domain with a 0.2mØ circle in the middle.
I am using simpleFoam. (is that ok?)
Left boundary = inlet.
Right boundary = outlet.
bottom boundar = upper boundary = wall (moving with same speed as inlet value)
circle = wall

Questions:
1. What should i do with the "interior" regarding U,p,k,epsilon?

2. How do I know the smallest cellsize dx if i have converted my case from fluent? (i dont have any BlockmeshDict)

3. After having guessed arbitrary answers to the above questions I get
"BICCG: Solving for Ux: solution singularity"
etc for Uy,p,epsilon,k
"time step continuity errors: sum local = nan, global = nan, cumulative = nan"


Hope you dont mind my rookie-questions.

Thanx!!

/ham
ham is offline   Reply With Quote

Old   May 31, 2006, 13:05
Default You can look in the tutorial f
  #2
Member
 
Pierre Le Fur
Join Date: Mar 2009
Location: UK
Posts: 60
Rep Power: 17
pierre is on a distinguished road
You can look in the tutorial for simpleFoam. typical conditions/values for walls, inlet and outlet are in there. If you're using simpleFoam, I assume you're doing a steady-state calculation. So initial internal values can be set to any guessed values, it is not really important (I think), again look at the tutorial. For bottom and upper boundary, are they really walls or you just want to set it far free stream conditions?

try running CheckMesh

Hope that helps

Pierre
pierre is offline   Reply With Quote

Old   June 1, 2006, 03:11
Default Thank you very much. I will
  #3
ham
Member
 
Marcus Hammar
Join Date: Mar 2009
Posts: 33
Rep Power: 17
ham is on a distinguished road
Thank you very much.
I will look into this now.
Hope Ill get it to work...

Have a nice day.

/Marcus
ham is offline   Reply With Quote

Old   June 1, 2006, 03:47
Default Okey, now it works better. htt
  #4
ham
Member
 
Marcus Hammar
Join Date: Mar 2009
Posts: 33
Rep Power: 17
ham is on a distinguished road
Okey, now it works better.
I compared all my files against the files in the tutorials until I found the error.

I have to say its a bit embarrasing, but the kinematic viscosity was set to 0. For my defence I thought the default value of this property was set to something more logical...

Now i just have to make sure that the freestream keep on running and does not end after the first iteration

Thanx again
Marcus
ham is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
error during solution initialization Muhammad Usman Qureshi FLUENT 7 March 31, 2008 08:26
Error modelling for a nonconverged solution martapajon OpenFOAM Running, Solving & CFD 2 August 16, 2007 14:13
solution singularity litonx OpenFOAM Running, Solving & CFD 1 February 21, 2007 02:32
Size of neighbour cells cause to solution error. Stanislav Kraev FLUENT 2 March 27, 2006 01:38
Urgent : Error in the Solution Prasad Laxman Kane FLUENT 1 August 19, 2002 08:06


All times are GMT -4. The time now is 06:02.