CFD Online Logo CFD Online URL
Home > Forums > FLUENT

Questions about a Turbulent Flat Plate Case

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

LinkBack Thread Tools Display Modes
Old   August 11, 2009, 12:02
Default Questions about a Turbulent Flat Plate Case
Join Date: Apr 2009
Posts: 78
Rep Power: 10
tstorm is on a distinguished road
I'm trying to validate a user-defined turbulence model. As a baseline, I'm generating results using the Spalart-Allmaras, k-e, and k-w turbulence models for a turbulent flat plate. Freestream velocity is 1.46 m/s, with the molecular viscosity dropped to about 1.5e-7.

The plate is 1m long, with 0.2m in front of the plate and 0.2m behind the plate, both defined by the 'symmetry' boundary condition. At the symmetry boundaries upstream and downstream of the plate, the cases are showing very high turublence kinetic energy. Is that right? Can anyone explain why I'm seeing this?

Here's a contour plot of k:


tstorm is offline   Reply With Quote

Old   August 11, 2009, 14:12
New Member
holger thiele
Join Date: Jul 2009
Posts: 2
Rep Power: 0
holg is on a distinguished road
I will give you my thoughts: so if you have a symmetry condition in front the plate, you have a stagnation point at the tip of your plate. that, might cause turbulence upstream. I assume you applied the no slip condition at the plate surface. So you will have a laminar sublayer which by definition has no turbulence. That might explain the low turbulence above the plate. Downstream the plate you have free air flow again an turbulence can spread. Did you use any wall functions? greets holger
holg is offline   Reply With Quote

Old   August 11, 2009, 14:16
Join Date: Apr 2009
Posts: 78
Rep Power: 10
tstorm is on a distinguished road
Thanks for your response - with the k-e model I'm using enhanced wall functions. y+ is below 1 though (99% of the wall cells are at about y+ = 0.5.) I'm seeing similar k contours for the k-w model as well, and I'm not using wall functions for that case. The wall does have a no-slip BC. I expected no turbulence in the laminar sublayer, but there doesn't seem to be any appreciable buildup of turbulence in the log layer, which I find surprising.
tstorm is offline   Reply With Quote


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
Turbulent Flat Plate Validation Case Jonas Larsson Main CFD Forum 0 April 2, 2004 10:25
Free convection flow over vertical flat plate Polly Main CFD Forum 1 February 11, 2003 14:25
Flat plate trouble Chetan Kadakia FLUENT 2 October 19, 2001 03:05
Supersonic flow over flat plate - best model Chris Rand FLUENT 4 October 3, 2000 06:58
Turbulent flow over flat plate Narayanan Main CFD Forum 1 May 8, 2000 07:03

All times are GMT -4. The time now is 17:00.