CFD Online Logo CFD Online URL
Home > Forums > FLUENT

K-eps what should converge first? what last?

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

LinkBack Thread Tools Display Modes
Old   May 2, 2007, 06:43
Default K-eps what should converge first? what last?
Posts: n/a
When converging on the residuals is there any order in how convergence should occur. Basically before i did a grid analysis to reduce the aspect ratio of elements near the airofoil i had "k" being the last to converge followed by epsilon and then continuity. Now i have continuity being the last to converge?? is there any problem with this??

Also when i try and scale my mesh evenly in X and Y obtain a finer mesh all my residuals go unstable and everything begines to rise from the first iteration? What is going on

My coarse mesh has lengths down about .0001 my next step mesh i wante lenghts down around .00005 Is this to small??
  Reply With Quote

Old   May 2, 2007, 06:52
Default Re: K-eps what should converge first? what last?
Posts: n/a
You shouldn't worry which order they converge, instead be thankful that they all did!

In my opinion if continuity converges last then the model isn't quite as good as if it converges first but you still get the same result both ways.

You may need to use relaxation factors if the solution is unstable or there may be a problem with your model. Try using the model you got to converge and gradually refining the mesh. The more cells you use the harder to converge and the more likely you need RF's.

I am however unsure what you mean by 'evenly in X and Y' and 0.001 means nothing without knowing more about the dimensions of the geometry. You should take your model to a lecturer/researcher.


Check all boundary conditions and the quality of the mesh.

  Reply With Quote


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
Laminar doesn't converge; Turbulent models do? Amit FLUENT 11 April 23, 2015 22:55
HELP !In relaxtion factor converge is taken or not MANOJ KUMAR FLUENT 5 September 22, 2005 04:16
Converge problem for multiphase flow Jen FLUENT 2 September 8, 2005 08:47
Converge problem for multiphase flow Jen FLUENT 4 July 20, 2005 16:52
VOF with tetra mesh doesn't converge Gregor FLUENT 1 March 1, 2005 14:09

All times are GMT -4. The time now is 14:15.