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

Yplus range for k-w model

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

Like Tree1Likes
  • 1 Post By azmir

Reply
 
LinkBack Thread Tools Display Modes
Old   June 23, 2005, 02:59
Default Yplus range for k-w model
  #1
Visser
Guest
 
Posts: n/a
Hi everyone,

I'm currently simulating incompressible, adiabatic flow through a 2d compressor cascade. I want to use the k-w turbulence model, but I am unsure of the y+ range. As far as I know it uses a wall function and thus I assume that the y+ range should be in the range 30<y+<100. Is this assumption correct? Does the adverse pressure gradient change the range of y+? References would be appreciated, as my results will be included in a technical paper.
  Reply With Quote

Old   June 23, 2005, 07:58
Default Re: Yplus range for k-w model
  #2
Visser
Guest
 
Posts: n/a
It seems that part of my post was cut off. Here's the rest: ...should be in the range 30 to 100. Is this correct? References would be appreciated, as this forms part of a technical paper.
  Reply With Quote

Old   June 23, 2005, 18:23
Default Re: Yplus range for k-w model
  #3
Sheila
Guest
 
Posts: n/a
For high Reynolds number cases y+ should be aroound the range you've mentioned so that your first cell is NOT in the laminar sublayer. However, for low Reynolds number cases it should be lower, and in particular whne you are more interested in boundary layer related phenomena y+ should be below 1. For more information, you can have a look at "An introduction to Computational fluid dynamics, The finite volume method" by H K Versteeg & W Malalasekera.
  Reply With Quote

Old   June 28, 2005, 05:48
Default Re: Yplus range for k-w model
  #4
azmir
Guest
 
Posts: n/a
The k-w model of Wilcox was originally not based on wall function or hi-Re formulation as I understood it unlike the kw-SST.

I don't think locating the first node near the wall within y+ of less than 30 or 70 would create a problem for k-w original as it was not based on wall function. However, in Star-CD the k-w seems to have both low-Re and high-Re options and so it is not clear (to me at least). Would appreciate some input.

Visser, refer quickly this link below before reading more texts.

https://pronet.wsatkins.co.uk/marnet...nes/guide.html
karthikkaero likes this.
  Reply With Quote

Old   July 6, 2005, 03:33
Default Re: Yplus range for k-w model
  #5
Visser
Guest
 
Posts: n/a
Sheila is right. The high-Re k-w uses a wall function, so the y+ range should be between 30 and 100. For low-Re k-w the y+ should be less than 1. A certain number of cells (not sure how many) should be in the boundary layer when using the low-Re k-w.
  Reply With Quote

Old   August 27, 2005, 01:56
Default Re: Yplus range for k-w model
  #6
Dhruv Baronia
Guest
 
Posts: n/a
Hi,

Can you tell me how to plot wall function values in prostar.Also what will happen if the values of y+ goes below 30 in case of high Re k-w model.
  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
turbulence model and yplus flying_dutchman Main CFD Forum 2 February 22, 2009 18:53
YPlus Values and SST Model Jenny CFX 1 June 22, 2008 18:47
Standard range of y+ for LES model? Pawan FLUENT 0 December 9, 2007 05:16
Model size range Alberto Guerra CFX 0 January 29, 2006 06:20
RNG ke model & Yplus value Pete CFX 2 February 16, 2005 02:11


All times are GMT -4. The time now is 12:25.