CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

periodic fully developed flow in pipe

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

LinkBack Thread Tools Display Modes
Old   January 9, 2004, 13:14
Default periodic fully developed flow in pipe
Posts: n/a
I am trying to do a very basic simulation. It is to obtain fully developed flow in a pipe of constant cross section.I want to biuld the mesh so that there are periodic bcs. This way I don't need to biuld a very long pipe.

How do I build such a mesh?

I have tried linking the in and out and then meshing. However, the resulting mesh is only on the faces and the pipe wall, not in the volume even though I requested a volume mesh.

Can anyone help with this very simple dilema?

  Reply With Quote

Old   January 12, 2004, 05:12
Default Re: periodic fully developed flow in pipe
Andrew Garrard
Posts: n/a
well, periodic, I assume that you are doing a 3D problem, if you request a volume mesh in gambit, then you should either get a volume mesh or an error tell you why a mesh has not been generated in the bottom part of the screen. What is the error you are recieving?
  Reply With Quote

Old   January 12, 2004, 07:58
Default Re: periodic fully developed flow in pipe
Posts: n/a
Yes. 3D pipe. When I have not mesh on a face and request a volume mesh the error is: Face.1 could not be converted to a submappable region.

When I first mesh a face and then request a mesh of the volume I get the same error.

I'm not sure what I'm doing wrong. I just want to have a 3D pipe with periodic bcs so I can obtain fd flow profile.
  Reply With Quote

Old   January 12, 2004, 10:38
Default Re: periodic fully developed flow in pipe
Posts: n/a
is there any hole in face 1. are number of nodes equal on opposite sides?
  Reply With Quote

Old   January 12, 2004, 12:53
Default Re: periodic fully developed flow in pipe
Posts: n/a
There does not appear to be any hole in the face. The number of nodes are the same on both faces.

To create the geometry I simply chose to create a volume on a predefined primative, choosing cylinder.

Then I go to mesh and choose to mesh the first end face. Then go to mesh the volume choosing the volume and the meshed end face as the source.

I get the same error.

What am I doing wrong?
  Reply With Quote

Old   January 12, 2004, 16:57
Default Re: periodic fully developed flow in pipe
Posts: n/a
My preferred way to mesh any cylindrical area to get a good mesh but may not work for this problem:
  • Use a face plan larger than your cylinder that cuts through it at the centerline.
  • Use the face-split to split the circular faces with this face (connected and retained, but not bidirectional).
  • Use the split line on each of the 2 new edges to split the line exactly 0.5 along it's length (that is, adding the center point to each face now).
  • Under the mesh face tool, set this new point for each of the 4 new faces to be a tri-element vertex.
  • Mesh the radii edges as desired. (Fixed interval is good, but in a pipe flow problem, you probably want to have a finer edge near the edge/wall - you could also use a boundary layer specification here if you need better control on the fineness of this mesh) - Make sure the number of edge points is even.
  • Mesh the circumfrence of the faces as desired, but make sure the number of mesh points is even.
  • Now mesh each of the 4 end faces. This should give you, by default, a nice radial pattern from the center point.
  • Mesh the lengthwise edge as desired
  • Mesh the volume at this point (the other face, along the body of the cylinder, will be generated automatically) using the hex/wedge/cooper scheme.
I've yet to have any problems when generating a system in this fashion, as opposed to letting Gabmit try to generate the end-cap face mesh which is typically quad/pave, and tends to be ugly. This gives you regular mesh elements near the walls all along the circumfrence of the tube.
  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
on fully developed duct flow yfyap Main CFD Forum 6 November 7, 2012 10:59
Fully developed flow ,CEL expression kmgraju CFX 0 August 6, 2010 04:15
Fully developed flow profile icfd Main CFD Forum 3 May 20, 2009 22:21
Fully Developed Flow at an Inlet Ed Mueller CFX 5 January 13, 2009 12:50
profile for fully developed turbulent duct flow jeff Main CFD Forum 1 November 14, 2001 22:35

All times are GMT -4. The time now is 19:38.