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

problem with rotating mesh

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 9, 2007, 03:49
Default problem with rotating mesh
  #1
viet
Guest
 
Posts: n/a
Hi all,

I face a problem with rotating mesh as follows: In a 2D transient fluid domain, there is a ellipse wall or oval wall. This wall can rotate about is axis with sinusoidal function, let's say theta = A*sin(w*t). I write the functions of motion in x and y direction to apply to the moving mesh, but I could not get the result. The error always appears due to the mesh distortion when I run the problem.

My functions in CEL are: XDIS = r*cos(theta)-r and YDIS = r*sin(theta). Are these functions correct? Please help me.
  Reply With Quote

Old   March 9, 2007, 06:43
Default Re: problem with rotating mesh
  #2
Joe
Guest
 
Posts: n/a
The CFX mesh motion definitions and options are rather counter intuitive.

There are two possibilities: Either your motion definition is incorrect or you are being too aggressive in the motion demanded per timestep.

Reduce the amplitude of the oscilation to check that your formulation is correct.
  Reply With Quote

Old   March 9, 2007, 09:09
Default Re: problem with rotating mesh
  #3
longbow
Guest
 
Posts: n/a
If you want to calculate moving distance of a node between two timesteps, XDIS should be r*cos(A*sin(omega*(t+dt)))-r*cos(A*sin(omega*t)), while YDIS be r*sin(A*sin(omega*(t+dt)))-r*sin(A*sin(omega*t)).
  Reply With Quote

Old   March 9, 2007, 10:22
Default Re: problem with rotating mesh
  #4
viet
Guest
 
Posts: n/a
Hi, Thanks for your response, I follow your suggestions but my problem still can not be solved. I think my input function is not correct. First, I try to simulate a simple problem in which a circle wall rotates harmonically about its axis with a sinusoidal function alpha=A*sin(omega*t). Can you suggest any moving mesh function for that? Thank you
  Reply With Quote

Old   March 9, 2007, 14:31
Default Re: problem with rotating mesh
  #5
longbow
Guest
 
Posts: n/a
Does the center of circle wall move? What's the rotating axis of it, x, y, or z?
  Reply With Quote

Old   March 10, 2007, 00:16
Default Re: problem with rotating mesh
  #6
viet
Guest
 
Posts: n/a
The circle wall is in xy-plane. It doesn't have any translation movement, but rotates harmonically about its center axis (z-axis). Thank you in advance.
  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
Mesh motion with Translation & Rotation Doginal CFX 2 January 12, 2014 07:21
[Gmsh] 2D Mesh Generation Tutorial for GMSH aeroslacker OpenFOAM Meshing & Mesh Conversion 12 January 19, 2012 04:52
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55
Problem with Output to .cfx5 mesh Ben CFX 4 January 24, 2008 18:47
How to control Minximum mesh space? hung FLUENT 7 April 18, 2005 10:38


All times are GMT -4. The time now is 17:09.