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

Global Length

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 19, 2006, 09:54
Default Global Length
  #1
Andres Bernal
Guest
 
Posts: n/a
Hi,

I'm working with an airfoil dimensioned in a unitary way..The Cd looks like very similar but lift don't match reality..

In the .out file I checked a parameter called Global Length which it's very different from the size I decided for the airfoil...this parameter makes the Re number change from 600e3 to 64.2e3...

Does anyone have any Idea?...I have to work with the foil in real size...since i'ts an dimensionless analisys?

Thanks in advance,

Andres.
  Reply With Quote

Old   December 20, 2006, 07:18
Default Re: Global Length
  #2
Joe
Guest
 
Posts: n/a
Make sure you used the correct length unit when importing the mesh into Pre. If you created in mm and imported in m there is obviously going to be a problem.
  Reply With Quote

Old   December 20, 2006, 10:51
Default Re: Global Length
  #3
Robin
Guest
 
Posts: n/a
Hi Andres,

The solver can't determine what the significant length is in a simulation. As a conservative guess, it uses the cube root of the volume of your entire domain. A more agressive guess is to use the maximum dimension of the bounding box.

This length scale is only used to calculate the auto-timescale and generate warnings if the corresponding estimate of the Reynolds number is out of the range of you turbulence model selection. Otherwise it has no influence on your solution.

Regards, Robin
  Reply With Quote

Reply

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
How to write k and epsilon before the abnormal end xiuying OpenFOAM Running, Solving & CFD 8 August 27, 2013 15:33
Upgraded from Karmic Koala 9.10 to Lucid Lynx10.04.3 bookie56 OpenFOAM Installation 8 August 13, 2011 04:03
Convergence moving mesh lr103476 OpenFOAM Running, Solving & CFD 30 November 19, 2007 14:09
IcoFoam parallel woes msrinath80 OpenFOAM Running, Solving & CFD 9 July 22, 2007 02:58
Could anybody help me see this error and give help liugx212 OpenFOAM Running, Solving & CFD 3 January 4, 2006 18:07


All times are GMT -4. The time now is 08:44.