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

Axis-symmetry in cartisian coordinates

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 27, 2004, 11:19
Default Axis-symmetry in cartisian coordinates
  #1
djemai
Guest
 
Posts: n/a
Hello, Is it possible to impose the symmetry BC for an axis-symmetric problem in cartisian coordinates? than you.
  Reply With Quote

Old   December 27, 2004, 21:15
Default Re: Axis-symmetry in cartisian coordinates
  #2
Mani
Guest
 
Posts: n/a
Yes, it's possible. What is the geometry and what are the flow conditions in your problem?
  Reply With Quote

Old   December 28, 2004, 09:04
Default Re: Axis-symmetry in cartisian coordinates
  #3
MER
Guest
 
Posts: n/a
Hi Mani; I use a cylindrical tube with inflow conditions at the inlet, outlet conditions at the outlet and symmetry for the half domain. thanks.
  Reply With Quote

Old   December 28, 2004, 15:35
Default Re: Axis-symmetry in cartisian coordinates
  #4
Mani
Guest
 
Posts: n/a
Just making sure: what exactly do you mean by "half domain"? Is that really half of the 3-D pipe, i.e. you have a 3-D grid for half of the circumference? More likely you mean, that you discretize half of the radial cross-section with a 2-D Cartesian grid. Sorry to be so specific, but if you really want it to be axisymmetric, you would rather do the latter. The symmetry condition should work. Do you have any problems with that, or why are you asking? Maybe you can describe your problem in more detail.
  Reply With Quote

Old   December 29, 2004, 06:11
Default Re: Axis-symmetry in cartisian coordinates
  #5
MER
Guest
 
Posts: n/a
I discretize half of the radial cross-section with a 2-D Cartesian grid. the problem that I have encountred that I have lost the symmetry in time when I simulate the motion of a bubble. perhapse, I haven't implememted the boundary condition of symmetry correctly or the grid chosen is not accurate.
  Reply With Quote

Old   December 29, 2004, 14:49
Default Re: Axis-symmetry in cartisian coordinates
  #6
Mani
Guest
 
Posts: n/a
The way you calculate the flow, i.e. the choice of your domain and the boundary conditions, inherently implies axisymmetry. I don't see how you can "loose" symmetry in time. Regardless of the accuracy of the solution, it must be axisymmetric by definition. If you have a solution on an x-r cut (where x is the direction of the pipe axis, r is the radial direction) for r from zero (center line of pipe) to R (radius of pipe wall), then the 3-D solution is produced by rotating your solution about the pipe axis. It is therefore axisymmetric, and I don't understand how you can judge that it's not? Are the symmetric boundary conditions not satisfied?
  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
Symmetry or Axis B.C ?? L. Hamid Main CFD Forum 2 May 20, 2011 07:27
[ICEM] Symmetry axis not present in pre fipellac ANSYS Meshing & Geometry 0 May 20, 2011 06:53
regarding axis of symmetry bunny FLUENT 0 January 3, 2011 05:19
axis singularity for cylindrical coordinates daniel Main CFD Forum 0 May 9, 2006 18:45
Warning: Symmetry zone should actually be an axis Gerd FLUENT 0 September 29, 2005 10:14


All times are GMT -4. The time now is 04:44.