CFD Online Logo CFD Online URL
Home > Forums > FLUENT

HOW turbulene Grid (avoid too fine or too coarse)?

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

LinkBack Thread Tools Display Modes
Old   January 31, 2007, 20:42
Default HOW turbulene Grid (avoid too fine or too coarse)?
Posts: n/a
In "modeling turbulence" section of fluent Tutorial (Fluent6.2 User Guide), it reads as below:

Now, my question is:

How to make my grid adequate in practice?

Thanks for your specific suggestion.

99999999999999999999999999999999999999999999999999 999999999 11.12.1 Mesh Generation

If the flow is wall-bounded, and the wall is expected to significantly affect the flow,take additional care when generating the mesh. You should avoid using a mesh that is too fine (for the wall function approach) or too coarse (for the enhanced wall treatment approach). 99999999999999999999999999999999999999999999999999 999999999

  Reply With Quote

Old   February 1, 2007, 04:47
Default Re: HOW turbulene Grid (avoid too fine or too coar
Jonas Larsson
Posts: n/a
First you have to decide if you are going to use a wall-function model or if you want to have fully resolved boundary layers. Wall functions should have the first grid point at y+ between say 30 and 200. A fully resolved grid should have the first grid point at about y+ 1.

You can estimate the actual size of y+ using one of the tools in:

For further information about y+īsee:

By the way, in the last few years commercial codes have started to use a new type of mixed wall treatments, which to some extent avoids the need to either have a resolved wall (y+ 1) or a wall-function mesh (y+ between 30 and 200). If you want to use this make sure that your model does support this and it would also be good to run some kind of tests before you trust the results from a mixed wall-treatment simulation too much.
  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
Grid Independent Solution Chuck Leakeas Main CFD Forum 2 May 26, 2000 11:18
Algebraic Multigrid for nonuniform grid Joshua Lee Main CFD Forum 4 March 16, 2000 14:05
Non-uniform grid calculation Aspens Main CFD Forum 1 February 23, 2000 15:15
Grid Quality and the Solution Faraz Main CFD Forum 4 January 10, 2000 19:18
Numerical methods for discontinuous grid interfaces? Hansong Hang Main CFD Forum 12 September 16, 1998 22:26

All times are GMT -4. The time now is 10:24.