CFD Online Logo CFD Online URL
Home > Forums > FLUENT

2D representation of pipe for fully developed flow

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

LinkBack Thread Tools Display Modes
Old   November 19, 2008, 14:54
Default 2D representation of pipe for fully developed flow
Posts: n/a
Hello, I know there are analytical solutions to these flows but I am trying to show my class a short tutorial on fluent, and this is the topic that was most recently covered.

I am trying to model laminar fully developed flow in arbitrarily shaped pipes. The first one I am trying to do is flow inside of a square pipe. I started by just making a square, adding a grid to it and then setting the four sides to walls under the boundary conditions.

From there I'm not sure what to do. I can't use periodic boundary conditions on the face because it is just a 2-D representation...... any ideas?

Again, it is just a square pipe where the flow is into or out of the screen. I'm not sure how to get the periodic BC's to work and also not sure how I can set a pressure gradient (into or out of the screen).
  Reply With Quote

Old   November 20, 2008, 21:00
Default Re: 2D representation of pipe for fully developed
Paolo Lampitella
Posts: n/a
To get what you want you have to move to a fully 3D model of the squared duct and, once put the grid in fluent, give the periodic boundary condition on inflow and outflow (which you can temporarily define as just velocity inlet in gambit) through the TUI...if i remember well you have to type:


then you will be asked about the ID numbers of the two faces you want to make periodic (this information is available under the boudary condition panel of the GUI) and if you want a translational (your case) or rotational periodic boundary.
  Reply With Quote

Old   November 22, 2008, 09:43
Default Re: 2D representation of pipe for fully developed
Posts: n/a
paola,I want to know hao defind the periodic boundary condiction and velocity inlet boundary condiction at the sametime?
  Reply With Quote

Old   November 22, 2008, 11:01
Default Re: 2D representation of pipe for fully developed
Paolo Lampitella
Posts: n/a
You can't, the inlet velocity profile will emerge as part of the solution.

If you are primarily looking for the steady laminar velocity profile in a section of the duct, you can use a very short duct, set the periodic condition on the inflow-outflow boundaries, initialize the field with 0 and solve with the segregated pressure-based solver.

When you'll get your final solution, you will see that the inlet velocity profile is just the same as any other profile in any section of the duct. Then just get the contour in one of this sections and the work is done.
  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
Simulating fully developed flow in a pipe Tim Donohue CFX 1 November 20, 2007 21:24
UDF for fully developed turbulent pipe flow Maged FLUENT 1 June 11, 2005 10:37
periodic fully developed flow in pipe periodicbc FLUENT 5 January 12, 2004 16:57
fully developed laminar pipe flow wendy CFX 11 January 16, 2002 18:12
fully developed turbulent flow in a pipe Dipak Phoenics 3 July 20, 2000 05:53

All times are GMT -4. The time now is 02:55.