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

a problem

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 2, 2003, 08:40
Default a problem
  #1
liu
Guest
 
Posts: n/a
When I use Fluent to compute 3D flow field, the following information appears: ˇ°Turbulent viscosity limited to viscosity ratio of 1.000000+05 in 18 cells.ˇ± What does it mean? Do I need to reset any parameters? Do it affect computation results? Thank you!
  Reply With Quote

Old   March 3, 2003, 01:14
Default Re: a problem
  #2
zhhuang
Guest
 
Posts: n/a
1/check your model, shape and size,Maybe the size 2/check your fluid,the default is air,maybe your fuild is water or others
  Reply With Quote

Old   March 3, 2003, 03:08
Default Re: a problem
  #3
Raintung
Guest
 
Posts: n/a
I met with the same phenomenon. Can you explain in detail, please? What does the ˇ°sizeˇ± mean? The solver used is coupled and explicit. Thank you very much!
  Reply With Quote

Old   March 3, 2003, 05:24
Default Re: a problem
  #4
ff
Guest
 
Posts: n/a
Read in fluent user guide chepters about turbulence modeling and/or some books about turbulent modeling.

Regards, ff
  Reply With Quote

Old   March 3, 2003, 08:15
Default Re: a problem
  #5
zhhuang
Guest
 
Posts: n/a
Raintung,I mean maybe you create your model in Gambit,and the default length unit in Gambit is meter.while the real unit maybe is mm.But you forgot to scale the unit in Fluent,and the inlet mass is constant,the velocity will be dimiss.I hope I didn't confuse you! regards zhhuang
  Reply With Quote

Old   March 3, 2003, 09:51
Default Re: a problem
  #6
Raintung
Guest
 
Posts: n/a
Thank you! But,are there any other reasons? I don't know what should I do.
  Reply With Quote

Old   March 5, 2003, 05:03
Default Re: a problem
  #7
Marc Gugau
Guest
 
Posts: n/a
It means your turbulence model (I guess Standard k-e !?) calculates a turbulent viscosity that is higher than the maximum allowed value (solve/controls/limits). This often happens in stagnation points. You can check out the 18 cells by displaying 3d-contours of the interior-zone with a lower limit of 1e5. Furthermore you can avoid all this by choosing a more sophisticated turbulence model. Neverthless your computational result should only neglectably be affected.
  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
UDF compiling problem Wouter Fluent UDF and Scheme Programming 6 June 6, 2012 04:43
Gambit - meshing over airfoil wrapping (?) problem JFDC FLUENT 1 July 11, 2011 05:59
natural convection problem for a CHT problem Se-Hee CFX 2 June 10, 2007 06:29
Adiabatic and Rotating wall (Convection problem) ParodDav CFX 5 April 29, 2007 19:13
Is this problem well posed? Thomas P. Abraham Main CFD Forum 5 September 8, 1999 14:52


All times are GMT -4. The time now is 03:33.