CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

problem on Laminar flow in a pipe

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 19, 2012, 14:44
Default problem on Laminar flow in a pipe
  #1
Senior Member
 
Goutam Saha
Join Date: Dec 2011
Location: UK
Posts: 128
Rep Power: 5
Goutam is on a distinguished road
Since I have consider the same velocity (measured from the formula
Vc { 1 - (r/R)^2 } at the inlet and outlet Bcs, I am expecting a linear profile for velocity magnitude but I am getting a parabolic profile? Is this correct? Problem description is given below.


Fully developed Laminar flow in a pipe: (Solver: simpleFoam)


L = 1.2 m, R = 0.0295 m, D = 2R = 0.0519 m,
Re = 100, neu = 1.004 E -6 m^2/s.

Entrance length, Le = 0.3114 m, Avg Velocity, Vc = 0.001934 m/s.
At r = 0, Vmax = 2*Vc = 0.0038682 m/s.

Initial Condition: velocity = (0 0 0), Bcs: Inlet and outlet velocity, V = Vmax and wall velocity = (0 0 0).
Initial Condition for p = 0, Boundary condition for p: Inlet and Wall: Pressure gradient is zero, outlet : p = 0.

Thanks
Attached Images
File Type: jpg profile.jpg (31.2 KB, 20 views)

Last edited by Goutam; March 20, 2012 at 06:02.
Goutam is offline   Reply With Quote

Old   March 19, 2012, 18:58
Default
  #2
Senior Member
 
kmooney's Avatar
 
Kyle Mooney
Join Date: Jul 2009
Location: Amherst, MA USA - San Diego, CA USA
Posts: 285
Rep Power: 9
kmooney is on a distinguished road
The steady state velocity profile for a laminar flow in a pipe is parabolic. Unless I'm confused it looks as though you are in fact getting the correct solution.
kmooney is online now   Reply With Quote

Old   March 20, 2012, 06:13
Default
  #3
Senior Member
 
Goutam Saha
Join Date: Dec 2011
Location: UK
Posts: 128
Rep Power: 5
Goutam is on a distinguished road
Since, I have used parabolic velocity at the both ends (inlet and outlet) then the velocity profile should be a linear profile. Am I right?
Goutam is offline   Reply With Quote

Old   March 20, 2012, 10:37
Default
  #4
Senior Member
 
kmooney's Avatar
 
Kyle Mooney
Join Date: Jul 2009
Location: Amherst, MA USA - San Diego, CA USA
Posts: 285
Rep Power: 9
kmooney is on a distinguished road
Quote:
Originally Posted by Goutam View Post
Since, I have used parabolic velocity at the both ends (inlet and outlet) then the velocity profile should be a linear profile. Am I right?
What do you mean by "linear profile"? The pressure should decrease linearly from inlet to outlet if that's what you mean. Due to continuity, however, the velocity profile will not change.
kmooney is online now   Reply With Quote

Old   March 20, 2012, 11:13
Default
  #5
Senior Member
 
Goutam Saha
Join Date: Dec 2011
Location: UK
Posts: 128
Rep Power: 5
Goutam is on a distinguished road
Sorry, I got the error. my result was correct but I want to use parabolic BC but I have used uniform BC. I want to use U(x) = 2U_0 [ 1- (x/r)^2 ]. This is the problem.
Goutam is offline   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
Pipe Roughness in Laminar Flow Swarup FLUENT 1 October 7, 2005 09:40
LAMINAR PIPE FLOW S A Sabir Main CFD Forum 0 March 11, 2005 08:56
a laminar flow and heat transfer problem majestywzh FLUENT 1 April 16, 2003 03:39
looks simple,but confusing,a pipe flow problem! W.Z.H FLUENT 14 March 14, 2003 08:27
fluid flow fundas ram Main CFD Forum 5 June 17, 2000 21:31


All times are GMT -4. The time now is 08:41.