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

Strange velocity profile at the inlet for a flow inside a cylindrical pipe

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 2, 2012, 03:37
Default Strange velocity profile at the inlet for a flow inside a cylindrical pipe
  #1
New Member
 
Michel FALL
Join Date: May 2012
Posts: 1
Rep Power: 0
michmich is on a distinguished road
Hi Foamers,

I've searched in the forum for some pieces of advice but I couldn't find all the details I wanted. So here is my problem:

I'm running simpleFoam in laminar mode to solve the simple case of a fluid going through a cylindrical pipe.
First I runned the solver for a pipe long enough to see the boundary layer fully developed and then I did the same with a smaller pipe to see if I get the same velocity profile.
In my case the boundary layer needs 5 meters to get fully developed, so the big pipe is 6m long and the small one 1m.
To run it faster I've considered a rectangular mesh in 2D.

My 0/U file:

inlet
{
type fixedValue;
value uniform (0.01 0 0);
}
outlet
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}
wall
{
type fixedValue;
value uniform (0 0 0);
}

My 0/p file

inlet
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
wall
{
type zeroGradient;
}

The problem is the velocity profile at the inlet as you can see above.

small.jpg

big.jpg

To my mind it's impossible to have an acceleration of the fluid close to the wall at the inlet...

Is there somebody who knows what's wrong with my boundary layer or who can give me some pieces of advice?

Cheers,

Michel
michmich 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
Export & Import Velocity profile as Inlet eRzBeNgEl STAR-CCM+ 6 March 26, 2012 05:16
Velocity inlet boundary condition for porous medium Chander CFX 3 March 11, 2012 22:18
ATTENTION! Reliability problems in CFX 5.7 Joseph CFX 14 April 20, 2010 15:45
FSI- Pipe- uniform velocity profile inlet Absy Main CFD Forum 0 April 6, 2010 03:01
reversed flow at velocity inlet / mass flow inlet ib FLUENT 1 March 26, 2007 13:11


All times are GMT -4. The time now is 03:03.