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

*** Guidelines on Boundary Layer Meshing ***

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 18, 2008, 11:27
Default *** Guidelines on Boundary Layer Meshing ***
  #1
Carlos
Guest
 
Posts: n/a
Hello,

I am about to mesh a large vehicle with a boundary layer mesh but I don't know what parameters to put in. I have no problems creating the b.l. mesh but I'm unsure how many layers to use, what height to put the first cell for a y+ of 30-50 and what expansion factor to use.

Has anybody used these before, can you give me your suggestions, maybe with a reference or two? In the past people have suggested 5 layers but I am happy to listen to any advice.

Any advice would be greatly appreciated as this represents the final stage of my PhD work and I only have 6 months left! So I want to get it right. As i said, any references would be very helpful.

Many thanks for your help,

Carlos.
  Reply With Quote

Old   March 19, 2008, 00:19
Default Re: *** Guidelines on Boundary Layer Meshing ***
  #2
Hirdesh
Guest
 
Posts: n/a
5-7 layer is sufficient,expansion ratio should be 1.1 - 1.2.
  Reply With Quote

Old   March 19, 2008, 07:44
Default Re: *** Guidelines on Boundary Layer Meshing ***
  #3
Ralf Schmidt
Guest
 
Posts: n/a
hi!

the expansion ratio of 1.1 to 1.2 is ok... but i would take more BL rows!

Depending on the results you are interested in, i would choose the turb. model and therfor set y+. For calculation of heat or mass transfer and draq i would suggest the sst k-w model with y+ between 1 and 5.

The total thickness of the BL cells should be about the same size as the real velocity bl - the area, where the vel. is below 99 % of the free stream vel.

Hope, that helps Ralf
  Reply With Quote

Old   March 19, 2008, 09:29
Default Re: *** Guidelines on Boundary Layer Meshing ***
  #4
Corrado
Guest
 
Posts: n/a
Hi

for a 2D analysis of wing with fowler flap, I used expansion 1.2 and 25 layers.I didn't try with fewer layers. With Spalart-Almaras turb. model I get a mean value of y+ of 0.7.

Corrado
  Reply With Quote

Reply

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 meshing rav_aero FLUENT 1 September 21, 2007 09:51
How to do boundary layer meshing in a 3D diffuser Durgendra Main CFD Forum 1 June 26, 2006 08:18
Problems in boundary layer meshing Henriques FLUENT 1 February 18, 2006 06:54
Boundary Layer Meshing of a nosecone Chris FLUENT 1 March 15, 2005 13:42
boundary layer meshing santosh FLUENT 6 November 1, 2001 18:54


All times are GMT -4. The time now is 13:50.