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

Difference between laminar and turbulent separatio

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

Reply
 
LinkBack Thread Tools Display Modes
Old   September 20, 2007, 07:43
Default Difference between laminar and turbulent separatio
  #1
NIK
Guest
 
Posts: n/a
What is the difference between laminar (LS) and turbulent separation (TS) for a flow over circular cylinder?
  Reply With Quote

Old   September 20, 2007, 09:00
Default Re: Difference between laminar and turbulent separ
  #2
gocarts
Guest
 
Posts: n/a
If it's any help try Dimples on Golf Balls for an explanation of laminar and turbulent boundary layer separation over a sphere - I think you'll find the reasoning similar to the flow over a cylinder.
  Reply With Quote

Old   September 20, 2007, 12:50
Default Re: Difference between laminar and turbulent separ
  #3
Gerrit Groot
Guest
 
Posts: n/a
What difference do you want to know about?

The turbulent one will have a smaller wake, this is why skaters use strips on their arms (streamlined shapes like cycling helmets are not allowed for them).

  Reply With Quote

Old   September 21, 2007, 05:06
Default Re: Difference between laminar and turbulent separ
  #4
NIK
Guest
 
Posts: n/a
Thanks. In one paper by Trevin et. al, he talks about LS (laminar separation) and TS (turbulent separation) at Re=140000. How can we get laminar or turbulent separation using the same code?
  Reply With Quote

Old   September 21, 2007, 05:25
Default Re: Difference between laminar and turbulent separ
  #5
Gerrit Groot
Guest
 
Posts: n/a
First of all, I suppose your code is 2D.

Does it have a transition model?
  Reply With Quote

Old   September 21, 2007, 07:28
Default Re: Difference between laminar and turbulent separ
  #6
NIK
Guest
 
Posts: n/a
My code is 3D DES using S-A turbulence model.
  Reply With Quote

Old   September 21, 2007, 07:41
Default Re: Difference between laminar and turbulent separ
  #7
Gerrit Groot
Guest
 
Posts: n/a
Ooh, isn't that a bit heavy for cylinder flow? Why don't you use a 2D solver? You run in fully turbulent then I suppose?

Anyway, if you only want to see the difference in the wake for engineering purposes, I think it's tabulated somewhere, maybe in the drag book by Hoerner.

  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
Laminar doesn't converge; Turbulent models do? Amit FLUENT 11 April 23, 2015 22:55
CFX Treatment of Laminar and Turbulent Flows Jade M CFX 6 January 26, 2013 11:11
SimpleFoam: Laminar vs. Turbulent Convergence JasonG OpenFOAM 0 June 2, 2011 08:29
Laminar vs Turbulent Navier-Stokes truman Main CFD Forum 6 March 7, 2011 14:44
difference of the laminar and turbulent model duaiduaihu FLUENT 0 August 13, 2010 23:40


All times are GMT -4. The time now is 20:04.