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

Fully developed flow boundary condition

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

Like Tree18Likes
  • 2 Post By jits_aps90
  • 4 Post By AlanR
  • 10 Post By ngj
  • 1 Post By ngj
  • 1 Post By nihossain

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 28, 2009, 10:24
Question Fully developed flow boundary condition
  #1
New Member
 
Jitender Singh Yadav
Join Date: Jul 2009
Location: Pune (India)
Posts: 11
Rep Power: 17
jits_aps90 is on a distinguished road
I am working on Jets in Crossflow (JICF) problem as a part of my Masters thesis.
At a face, which is inlet for the jet, I want to implement "A FULLY DEVELOPED FLOW" condition, that will help saving my length of the jet pipe, otherwise I will have to work on :

L(entrance) = 0.06 * Re * D. (for laminar flow)

To avoid this, I want to implement such a condition.

How I can implement such a condition in OpenFOAM.

Thanks a lot.
Luttappy and CFD_beginner12 like this.
jits_aps90 is offline   Reply With Quote

Old   December 31, 2009, 01:51
Default
  #2
Member
 
Alan Russell
Join Date: Aug 2009
Location: Boise, Idaho USA
Posts: 61
Rep Power: 17
AlanR is on a distinguished road
jits,

One method is to set up the inlet profile with your fully developed flow. The /incompressible/simpleFoam/pitzDailyExptInlet tutorial shows how to do this. There is a file called /constant/boundaryData/inlet/points that has a list of points where you will set your profile. The file /constant/boundaryData/inlet/0/U is where you store the velocity (and other) values for each point. I put the formula in a spreadsheet, calculate the velocity profile data and copy it to the Foam file - this method is working well for me. Good luck,

Alan
AlanR is offline   Reply With Quote

Old   January 4, 2010, 00:57
Default
  #3
New Member
 
Jitender Singh Yadav
Join Date: Jul 2009
Location: Pune (India)
Posts: 11
Rep Power: 17
jits_aps90 is on a distinguished road
thanks AlanR,
i shall surely try this , seems this should work, even if its 3d I flow, I hope the same things should hold.
thanks once again.
jits_aps90 is offline   Reply With Quote

Old   January 4, 2010, 05:43
Default
  #4
ngj
Senior Member
 
Niels Gjoel Jacobsen
Join Date: Mar 2009
Location: Copenhagen, Denmark
Posts: 1,903
Rep Power: 37
ngj will become famous soon enoughngj will become famous soon enough
Hi Jitender

Another approach is to look in the example

~/OpenFOAM/OpenFOAM-1.6.x/tutorials/incompressible/pisoFoam/les/pitzDailyDirectMapped

where a mapping procedure is carried out between to planes with a given offset between them. The profile from the interior plane is mapped back on to the inlet, hence between these two planes you basically have an infinitely long pipe, and since you are considering laminar flows, then the distance between the two planes is of minor importance as far as the validity of the velocity (and turbulence) profile(s) goes.

I have some nice pictures of a laminar jet in a laminar cross flow on which I performed a POD-analysis, so if you are interested in seeing the results just drop me an email.

Happy New Year,

Niels
ngj is offline   Reply With Quote

Old   January 4, 2010, 06:10
Default
  #5
New Member
 
Jitender Singh Yadav
Join Date: Jul 2009
Location: Pune (India)
Posts: 11
Rep Power: 17
jits_aps90 is on a distinguished road
thanks a lot and i wish the same for you.

i viewed the pitzDailyMapped case, but i couldn't find out at what offset the values are mapped.
and how many times the values are mapped. Are they mapped untill the flow becomes fully developed.

thanks
jits_aps90 is offline   Reply With Quote

Old   January 4, 2010, 06:52
Default
  #6
ngj
Senior Member
 
Niels Gjoel Jacobsen
Join Date: Mar 2009
Location: Copenhagen, Denmark
Posts: 1,903
Rep Power: 37
ngj will become famous soon enoughngj will become famous soon enough
Hi

Look at the following file in the tutorial case: "system/changeDictionaryDict". Running the utility changeDictionary before running the application changes the boundary type in constant/polyMesh/boundary with whatever is stated in the first file. In the first file you also state the offset vector of the given patch.

I will send you an email later today with my results.

Bests,

Niels
Asgarian likes this.
ngj is offline   Reply With Quote

Old   September 8, 2011, 12:29
Wink Hi
  #7
New Member
 
Ali Asgarian
Join Date: Jul 2011
Location: Toronto, CA
Posts: 4
Rep Power: 15
Asgarian is on a distinguished road
Hi,

I guess this page was active long before, but it is still worthy to ask my question.
I need to simulate fully developed flow in a geometry (e.g. pipe) with one inlet and one outlet. I prefer to avoid modelling a long pipe; can I implement the same method to model small piece of pipe instead?

Tanx
Asgarian is offline   Reply With Quote

Old   November 2, 2011, 17:10
Default
  #8
New Member
 
Naser Imran Hossain
Join Date: Sep 2011
Posts: 6
Rep Power: 15
nihossain is on a distinguished road
Quote:
Originally Posted by jits_aps90 View Post
I am working on Jets in Crossflow (JICF) problem as a part of my Masters thesis.
At a face, which is inlet for the jet, I want to implement "A FULLY DEVELOPED FLOW" condition, that will help saving my length of the jet pipe, otherwise I will have to work on :

L(entrance) = 0.06 * Re * D. (for laminar flow)

To avoid this, I want to implement such a condition.

How I can implement such a condition in OpenFOAM.

Thanks a lot.
Hey, do you have any idea how to do that in FLUENT? I'm having the same problem where I need a fully developed flow at the inlet but don't want to change the pipe length. Some help would be really appreciated.
BHUVANESH likes this.
nihossain is offline   Reply With Quote

Old   November 17, 2017, 09:34
Default fully developed inlet profile for 3D pipe flow
  #9
Member
 
Shafik Walakaka
Join Date: Oct 2017
Posts: 38
Rep Power: 9
walakaka is on a distinguished road
Quote:
Originally Posted by jits_aps90 View Post
thanks AlanR,
i shall surely try this , seems this should work, even if its 3d I flow, I hope the same things should hold.
thanks once again.

How did you manage to translate that code into 3D? I am trying to simulate a simple pipeflow with a fully developed profile at the inlet
walakaka is offline   Reply With Quote

Old   May 31, 2023, 07:17
Default
  #10
New Member
 
Murtadh
Join Date: May 2023
Posts: 4
Rep Power: 3
CFD_beginner12 is on a distinguished road
Hi all ,
how can I do the same in Ansys?
(maintain a fully developed profile at inlet)
CFD_beginner12 is offline   Reply With Quote

Reply

Tags
boundary condition, fully developed flow.

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
back flow at pressure out flow boundary condition durga Main CFD Forum 0 December 8, 2009 01:42
Writing an expression for fully developed flow! Usman CFX 12 December 20, 2007 12:26
fully developed flow JAS FLUENT 4 February 12, 2007 07:01
Fully Developed Boundary Condition at Duct Inlet Twiti CFX 1 January 24, 2005 02:31
fluid flow fundas ram Main CFD Forum 5 June 17, 2000 22:31


All times are GMT -4. The time now is 13:22.