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

Nan on LES dynamic models

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

Like Tree1Likes
  • 1 Post By henry

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 8, 2005, 13:52
Default Hi all, I am trying to use a
  #1
Member
 
diablo80@web.de
Join Date: Mar 2009
Posts: 93
Rep Power: 17
sampaio is on a distinguished road
Hi all,
I am trying to use a dynamic model for LES, but since the first iteration I got "nan" in all solvers...
Has anyone succeeded in using dyn models?
Do I need to do anything else, other than switch the name of the model in turbulenceProperties?
(I started with the "static" model, in my case 1Eq, and than after several timesteps, switched to dyn model)
Thanks,
Luiz
sampaio is offline   Reply With Quote

Old   March 8, 2005, 13:56
Default Do you have a zero turbulence
  #2
Senior Member
 
Hrvoje Jasak
Join Date: Mar 2009
Location: London, England
Posts: 1,902
Rep Power: 33
hjasak will become famous soon enough
Do you have a zero turbulence initial condition? That would do it - have a look at the files in zero directory and make sure they make sense.

Hrv
__________________
Hrvoje Jasak
Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk
hjasak is offline   Reply With Quote

Old   March 8, 2005, 13:59
Default Which dynamic model are you tr
  #3
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 22
henry is on a distinguished road
Which dynamic model are you trying? I have just tried dynSmagorinsky on the tutorial case and it ran fine.

There may be an issue with the dynamic models starting from a zero or even uniform U field. Try running with a non-dynamic model first and then restart with a dynamic model.
henry is offline   Reply With Quote

Old   March 8, 2005, 14:03
Default I dont think you can yet switc
  #4
Senior Member
 
Eugene de Villiers
Join Date: Mar 2009
Posts: 725
Rep Power: 21
eugene is on a distinguished road
I dont think you can yet switch turbulence models in mid-calculation.
eugene is offline   Reply With Quote

Old   March 8, 2005, 14:04
Default You can restart with a differe
  #5
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 22
henry is on a distinguished road
You can restart with a different turbulence model, I do it frequently.
henry is offline   Reply With Quote

Old   March 8, 2005, 14:07
Default Hi Henry, It ran fine with dy
  #6
Member
 
diablo80@web.de
Join Date: Mar 2009
Posts: 93
Rep Power: 17
sampaio is on a distinguished road
Hi Henry,
It ran fine with dynSmagorinski, but it blows with dynOneEq...
I did run first with a static (non-dyn) model.
Thanks a lot
sampaio is offline   Reply With Quote

Old   March 8, 2005, 14:10
Default OK, I see what is going on. T
  #7
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 22
henry is on a distinguished road
OK, I see what is going on. The problem is the dynamic models do ynot currently have stabilisation in the terms average(LL && MM)/average(MM && MM) where MM may be locally (or even globally) zero. I will look at the dynOneEq... and tell you what you need to change.
hua1015 likes this.
henry is offline   Reply With Quote

Old   March 8, 2005, 14:51
Default Try this http://www.cfd-on
  #8
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 22
henry is on a distinguished road
Try this

locDynOneEqEddy.C
henry is offline   Reply With Quote

Old   March 8, 2005, 16:41
Default Hi Henry, I tried but it did
  #9
Member
 
diablo80@web.de
Join Date: Mar 2009
Posts: 93
Rep Power: 17
sampaio is on a distinguished road
Hi Henry,
I tried but it did not worked.
Did it work for you?
Thanks.
Luiz
sampaio is offline   Reply With Quote

Old   March 8, 2005, 16:44
Default Hi Henry, I tried but it did
  #10
Member
 
diablo80@web.de
Join Date: Mar 2009
Posts: 93
Rep Power: 17
sampaio is on a distinguished road
Hi Henry,
I tried but it did not work.
Did it work for you?
Thanks.
Luiz
sampaio is offline   Reply With Quote

Old   March 8, 2005, 16:44
Default Yes, it worked fine for me. P
  #11
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 22
henry is on a distinguished road
Yes, it worked fine for me. Put some print statements in it to check you are calling the new functions, the ones with the limiters in are at the top of the file.
henry 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
Two-fluid models vs mixture models for bubbly flows Hansong Tang Main CFD Forum 6 December 8, 2009 04:21
Failed dimensional check with dynamic LES models alberto OpenFOAM Bugs 9 September 5, 2007 23:57
LES dynamic models fail dimensional check alberto OpenFOAM Running, Solving & CFD 0 June 11, 2007 14:23
Dynamic Mesh Models Marc Main CFD Forum 1 November 29, 2003 13:21
Dynamic Subgrid Models Bono Main CFD Forum 2 November 27, 2001 17:50


All times are GMT -4. The time now is 00:10.