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

LES with BFC

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 21, 2007, 18:53
Default LES with BFC
  #1
David
Guest
 
Posts: n/a
Hello, Since the previous posting about LES in PHOENICS, I have been trying to use LES in BFC. However, there is some odd thing going on. Using similar geometry and setting for each case, I find that the results from BFC is not identical with Cartesian case. Actually, I do not see any eddies develping using BFC, althogh I tried many variations of time step sizes and grid dimesions. Is there any library case using LES and BFC together or any publication using PHOENICS as such? Or is LES compatible with BFC in PHOENICS? Thank you in advance.
  Reply With Quote

Old   April 3, 2007, 06:18
Default Re: LES with BFC
  #2
Mike
Guest
 
Posts: n/a
I am not aware of any LES restriction for BFCs. The default grid filter for the Smagorinsky SGS model is one-third of the cell volume, as may be seen in the file /phoenics/d_earth/d_core/gxmxlen.htm. For wall-bounded flows, wall damping is advisable and so the LTLS variable must be solved to provide computation of the WDIS variable.

It might be a good idea to check whether the ENUT and LEN1 values are reasonable for BFC meshes. Check the values by hand for a few cells. It should be possible to restart from the Cartesian case, and perform a single-sweep run with the BFC case. The velocity fields will then be similar, but check whether the ENUT and LEN1 values returned for the BFC mesh are similar to those for the Cartesian mesh.

  Reply With Quote

Reply


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



All times are GMT -4. The time now is 00:07.