CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

BSL Automatic Wall Function - Shifted koordinates

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   April 26, 2007, 06:04
Default BSL Automatic Wall Function - Shifted koordinates
  #1
Sali
Guest
 
Posts: n/a
Dear forum members,

I currently play around with calculations of the turbulent flow in a straight pipe (cfx10). The grid consists of a 2d crossection (ogrid) orthogonal to the main flow direction. I tested different high-reynolds and low-reynolds grids. The k-epsilon model (on the high-re grid) sets the velocity for the the first inner vertex as expected (matches with the logarithmic law). With BSL-komega+automatic wall model, there is always an apparent shift in the coordinates. In the low-re Case , the asymptotic behaviour u+=y+ is matched if y+ is shifted by 1 if the dimension free wall distance of the first vertex is 1, by 2 if it is 2 and so on. I can only guess that u+=1 is always assumed for the first vertex (on the wall) in the low-re case? I dont understand how the manual explains the automatic wall function: "the location of the first mesh point is now virtually moved down through the viscous sublayer as the mesh is refined in the low-Re mode." Maybe somebody could explain this differently? In the high-re grid, the profile from the bsl calculation seems also shifted by some value but i dont quite see how.

Since these are simple calculations i guess that there is a simple answer, but i just dont see it at the moment.

Thanks a lot, Sali
  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
Automatic wall treatment in CFX Chander CFX 13 May 6, 2017 01:45
No results for solid domain Gary Holland CFX 10 March 13, 2009 04:30
Wall function problem in Fluent mefpz FLUENT 1 October 10, 2007 14:43
DecomposePar links against liblamso0 with OpenMPI jens_klostermann OpenFOAM Bugs 11 June 28, 2007 18:51
Wall function in adverse pressure gradients stephane baralon Main CFD Forum 11 September 2, 1999 05:05


All times are GMT -4. The time now is 20:45.