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

symmetric flow

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 26, 2010, 06:17
Default symmetric flow
  #1
Member
 
lehoang_mai's Avatar
 
User_CFD
Join Date: Mar 2010
Posts: 48
Rep Power: 16
lehoang_mai is on a distinguished road
Hi all friends! I simulated model 3D in symmetric flow and computed onehalf of flow. after iterations, I want to compute force(lift and drag) of model. But their values to small (half) in comparison with experiment's values.
Please tell me how to do! Thank you for reading! (sorry for my english)

Last edited by lehoang_mai; July 26, 2010 at 16:33.
lehoang_mai is offline   Reply With Quote

Old   July 27, 2010, 02:12
Default
  #2
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
You are computing one half of your model, and you are getting one half of expected result.........

Fluent doesn't multiply automatically the results for reaching the total result (ie: without symmetry). I mean it returned you the results for the computed domain (one half)
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   July 27, 2010, 05:30
Default
  #3
Member
 
lehoang_mai's Avatar
 
User_CFD
Join Date: Mar 2010
Posts: 48
Rep Power: 16
lehoang_mai is on a distinguished road
Thank -mAx- very much!
You're right, it returned me the results for one half of domain. But I viewed results in field flow (pressure, velocity....), they're same as in field flow of full domain. Do you know, how to calculate lift anf drag in symmetric situation in order that It returned me same results in full domain?
lehoang_mai is offline   Reply With Quote

Old   July 27, 2010, 06:34
Default
  #4
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
If you are computing one half of geometry, the pressure and velocity won't be multiply by 2 for the full domain.
it is a question of section.
For instance the pressure force on a body will be multiply by 2 for the full domain since the surface is double (projected forces normal to symmetry don't have to be multplied by 2, since they will be compensated).
To your question, then you need to give the right Area in the reference values.
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   July 27, 2010, 07:27
Default
  #5
Member
 
lehoang_mai's Avatar
 
User_CFD
Join Date: Mar 2010
Posts: 48
Rep Power: 16
lehoang_mai is on a distinguished road
Thanks you for reply!
And more little question from me. If I will compute one half of geometry, then the pressure force (and total force) on a body will be multiply by 2 for the full domain, isn't it?
lehoang_mai is offline   Reply With Quote

Old   July 27, 2010, 07:45
Default
  #6
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
yes, but not in the normal direction to your symmetry (here it should be 0)
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   July 27, 2010, 07:56
Default
  #7
Member
 
lehoang_mai's Avatar
 
User_CFD
Join Date: Mar 2010
Posts: 48
Rep Power: 16
lehoang_mai is on a distinguished road
Thanks you very much!
lehoang_mai is offline   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
Compressible flow, no data at the outlet mireis FLUENT 6 September 3, 2015 03:10
Steady state Ruben Main CFD Forum 43 May 7, 2011 04:32
Mass flow and U-Mom flow in CFX Zhihua Xie CFX 0 September 3, 2007 10:49
reversed flow at velocity inlet / mass flow inlet ib FLUENT 1 March 26, 2007 14:11
transform navier-stokes eq. to euler-eq. pxyz Main CFD Forum 37 July 7, 2006 09:42


All times are GMT -4. The time now is 01:23.