CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

Uneven velocity profile as inlet

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

Like Tree5Likes
  • 1 Post By hyFoam
  • 2 Post By piu58
  • 2 Post By Tobi

LinkBack Thread Tools Display Modes
Old   September 25, 2018, 02:57
Default Uneven velocity profile as inlet
New Member
Join Date: Jul 2018
Posts: 4
Rep Power: 2
Elm is on a distinguished road
Hi Foamers,

i do have an cylindric geometry with some inlet pipes at the bottom (see attachment).
Do you know if there is some inlet boundary conditions to model these pipes or an uneven velocity boundary?

I dont want to mesh all the small pipes, so please help me

(The picture of the pipes is just an example)

Elm is offline   Reply With Quote

Old   October 2, 2018, 15:59
New Member
Join Date: Mar 2017
Location: Glasgow, UK
Posts: 27
Rep Power: 3
hyFoam is on a distinguished road
Hi Elm,

Have you considered created two different patches while meshing? You could then use two different fixed values in 0/.

Elm likes this.
hyFoam is offline   Reply With Quote

Old   October 3, 2018, 02:49
Senior Member
piu58's Avatar
Uwe Pilz
Join Date: Feb 2017
Location: Leipzig, Germany
Posts: 590
Rep Power: 6
piu58 is on a distinguished road
You may give the velocity at your patch as nonuniform List<vector> . If you don't made this before I recommend to start with uniform velocity and analyze one of the result files. All you gave compact will be nonuniform there and you may see which velocity belongs to which coordinate.
You have to give a 0 file in the same structure.
atulkjoy and Elm like this.
Uwe Pilz
Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950)
piu58 is offline   Reply With Quote

Old   October 5, 2018, 05:18
New Member
Join Date: Jul 2018
Posts: 4
Rep Power: 2
Elm is on a distinguished road
@hyFoam: Yes, the two patches way is my "dirty" solutions ;-)

@piu58 Thanks for that hint, that seems the perfect solution for me!
Elm is offline   Reply With Quote

Old   October 5, 2018, 08:34
Super Moderator
Tobi's Avatar
Tobias Holzmann
Join Date: Oct 2010
Location: Augsburg
Posts: 2,152
Blog Entries: 6
Rep Power: 36
Tobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi

both ways will work, but I would prefer the first one - building two patches based on the following reason:
  • If you have two patches, you will catch the circular behavior of the inlets
  • If you have one patch, you will probably get a uniform mesh at the inlet (depending on the meshing strategy), and therefore, you can apply the velocities only to flat, non-curved faces which might influence your result.

However, personally, two patches do not seem to be a 'dirt' workflow. The way, Piu is explaining would be excellent, if:
  • The flat/curvature inlets does not influence your solution
  • You have the center points of the inlet pipes; a small codedFixed boundary condition while reading a file that contains the center while calculating the area of the circles and evaluate the included face centers while applying the velocity field, is beautiful, simple and modifiable
piu58 and Elm like this.
Keep foaming,
Tobias Holzmann
Tobi is offline   Reply With Quote

Old   October 8, 2018, 03:18
New Member
Join Date: Jul 2018
Posts: 4
Rep Power: 2
Elm is on a distinguished road
Thanks for you detailed answer Tobi!
I misunderstood the solution of hyFoam, i'll try both ideas
Elm is offline   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
combining parabolic inlet velocity profile with time varying velocity vector values jawapasu OpenFOAM 2 June 2, 2018 17:52
Velocity inlet BC profile antonio.c FLUENT 1 November 1, 2017 14:22
[swak4Foam] Inlet velocity profile for turbulent pipe flow using swak4Foam zordiack OpenFOAM Community Contributions 5 February 23, 2016 01:52
Strange velocity profile at the inlet for a flow inside a cylindrical pipe michmich OpenFOAM Running, Solving & CFD 0 July 2, 2012 03:37
Export & Import Velocity profile as Inlet eRzBeNgEl STAR-CCM+ 6 March 26, 2012 05:16

All times are GMT -4. The time now is 17:51.