CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum

Wall layer models

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

LinkBack Thread Tools Display Modes
Old   September 25, 2002, 11:57
Default Wall layer models
Posts: n/a
Hi everybody. I have a doubt regarding wall layer models. I have always used the standard wall functions, and to let the model work properly the near wall cell size has to be set in order to have the resulting y+ value between 30 and 100. In engine transient simulations this is not possible, because the flow conditions varies a lot, so it is difficult to keep the y+ value at the same location within the prescribed values. Furthermore, there are time instants where the velocity is almost zero, so y+ goes to 0, but there is no boundary layer because the fluid itself is standing!! So Im always in doubt when I have to set up the near wall cell size: what is a reasonable range of values of y+ that should I obtain?

In other words, are the wall functions model suitable for transient simulations? And what about separation?

Thank you in advance. Any help is welcome

  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
Boundary layer in a pipe Clementhuon OpenFOAM Native Meshers: snappyHexMesh and Others 6 March 12, 2012 13:41
Wall coordinates and boundary layer thickness bentmol Main CFD Forum 1 July 3, 2011 20:44
Combining BCs: wall - outlet. Boundary layer disappears MartinaF OpenFOAM Running, Solving & CFD 1 July 20, 2009 18:14
Multicomponent fluid Andrea CFX 2 October 11, 2004 05:12
Wall functions or low-Re models? J. P. Main CFD Forum 7 July 9, 1998 11:11

All times are GMT -4. The time now is 08:21.