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

Prediction of the critical Reynolds number

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

Like Tree1Likes
  • 1 Post By kalle

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 13, 2014, 12:45
Arrow Prediction of the critical Reynolds number
  #1
Member
 
Sami
Join Date: Nov 2012
Location: Cap Town, South Africa
Posts: 87
Rep Power: 13
Mehrez is on a distinguished road
Hi every one,
I'm using OpenFoam for simulating fluid flow in periodic media.
Do you have an idea on how can I predict the laminar/turbulent transitional Reynolds ?
Thank you in advance

Mehrez
Mehrez is offline   Reply With Quote

Old   May 15, 2014, 02:36
Default
  #2
Senior Member
 
Karl-Johan Nogenmyr
Join Date: Mar 2009
Location: Linköping
Posts: 279
Rep Power: 21
kalle is on a distinguished road
Well, in theory it should be possible using a DNS solver and sweep the Re-number, while assuring there is some small disturbances present. If you are below the critical number, the disturbance should decay, while if you are above, it should grow (into turbulence).

In practise it is tricky because you need to assure that your numerical viscosity is small enough (to be accurate in Re), and things like wall roughness may play significant role.

For an academic case (smooth wall), this is possible with OpenFOAM, (dnsFoam solver), but you would need massive computational resources (i.e. hyper-fine mesh)

K
Mehrez likes this.
kalle is offline   Reply With Quote

Old   May 15, 2014, 12:21
Default
  #3
Member
 
Sami
Join Date: Nov 2012
Location: Cap Town, South Africa
Posts: 87
Rep Power: 13
Mehrez is on a distinguished road
Hi dear Kalle,

Thank you for your answer.
Concerning my geometry, I have smooth walls. I have proceeded like you said by DNS (using IcoFoam solver with dimensionless NS equations).
I have got results but I want to verify if it is OK. I thought about the linear stability theory but OpenFoam doesn't have a such solver, so to validate my DNS results I need to adopt another method...
Best regards,

Mehrez
Mehrez is offline   Reply With Quote

Reply

Tags
laminar/turbulent, reynolds, transition, unsteady

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
decomposePar pointfield flying OpenFOAM Running, Solving & CFD 28 December 30, 2013 16:05
AMI interDyMFoam for mixer danny123 OpenFOAM Running, Solving & CFD 4 June 19, 2013 05:49
Stable boundaries marcoymarc CFX 33 March 13, 2013 07:39
Two way particle coupling in OF 2.0 and the particle reynolds number preichl OpenFOAM 7 February 9, 2012 16:38
Critical Reynolds Number Dipankar Chatterjee Main CFD Forum 0 September 4, 2002 11:01


All times are GMT -4. The time now is 05:45.