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

Ground Effect & Turbolence Model

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 10, 2002, 07:13
Default Ground Effect & Turbolence Model
  #1
Stefano
Guest
 
Posts: n/a
I have to study the Ground effect. Anyone knows which one is the best model for this kind of problems? - ke hi reynolds - ke low re - ke RNG - two layers Thanks
  Reply With Quote

Old   December 11, 2002, 06:25
Default Re: Ground Effect & Turbolence Model
  #2
Nicola
Guest
 
Posts: n/a
Hi Stefano,

what do you mean with "Ground effect"? The turbulence models are depending on Reynolds-number, wall roughness, the grid, etc. Read about them in the methodology-manual.
  Reply With Quote

Old   December 11, 2002, 07:09
Default Re: Ground Effect & Turbolence Model
  #3
Stefano
Guest
 
Posts: n/a
Nicola, i have a profile moving near a wall so i have zone at low Re number but also zone ( throw profile and wall ) at high velocity and high viscous effect. IN the past i used ke Hi Re number, now i'm using RNG model but the coefficients i found ( lift and drag) are different from ke ( expecially lift ), and the y+ values are often really high. I refine the mesh more times but y+ changes any time i change the value of U inlet velocity Have i to try 2-layers model?
  Reply With Quote

Old   December 17, 2002, 07:59
Default Re: Ground Effect & Turbolence Model
  #4
marco
Guest
 
Posts: n/a
Hallo Stefano!

For your problem the 2-Layer model should be the best choice. Anyway you need a very fine mesh: more then 10 cells should be contained in the boundary Layer! That means Y+ < 1.

Moreover, as the y+ values are depending on the flow velocity, you need feiner meshes for higher velocities.

Regards

Marco

  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
wing in ground effect meenakshi FLUENT 1 July 12, 2008 14:29
CFD in Ground Effect CFD Newbee FLUENT 1 January 14, 2008 16:27
Ground effect d bull CFX 1 April 12, 2007 09:39
Wing on ground effect John Tong FLUENT 0 September 5, 2006 00:31
Wing in Ground Effect mondal Main CFD Forum 2 June 28, 2006 07:12


All times are GMT -4. The time now is 15:56.