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

Boundary conditions on a wake cut

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

Reply
 
LinkBack Thread Tools Display Modes
Old   August 4, 2008, 20:18
Default I am modeling a 2D airfoil in
  #1
sjs
New Member
 
Sylvia Smullin
Join Date: Mar 2009
Posts: 10
Rep Power: 8
sjs is on a distinguished road
I am modeling a 2D airfoil in constant flow. My c-grid mesh (generated by an outside mesher) has a wake cut in it. By wake cut, I mean that there is a small gap along the chord direction behind the airfoil; this results from the way the C-grid is generated and OpenFoam's requirement of not having 2 overlapping points. Physically there should be no cut.
I want boundary conditions that specify that what flows out of one side of the cut flows in the other. Should this be cyclic boundary conditions (even though there is no cyclic symmetry, physically)?

Thank you.
Sylvia
sjs is offline   Reply With Quote

Old   August 5, 2008, 17:11
Default 1. merge the points (they are
  #2
Super Moderator
 
Mattijs Janssens
Join Date: Mar 2009
Posts: 1,416
Rep Power: 16
mattijs is on a distinguished road
1. merge the points (they are coincident I hope) then merge the two boundary faces into an internal face (using e.g. mergeOrSplitBaffles)

2. You could try cyclic. This requires strict conformity of point locations and face areas though - your mesher should output the cyclic faces ordered according to the OpenFOAM rules (see http://openfoamwiki.net/index.php/Write_OpenFOAM_meshes)
mattijs is offline   Reply With Quote

Old   August 6, 2008, 14:30
Default Thank you for suggestions. I g
  #3
sjs
New Member
 
Sylvia Smullin
Join Date: Mar 2009
Posts: 10
Rep Power: 8
sjs is on a distinguished road
Thank you for suggestions. I got the cyclic conditions right but the solution is funny. So I am trying to merge. I see lots of postings about faceSetDict, etc but I can't seem to get this quite right. Can you give me step-by-step instructions how to do this so I can use mergeOrSplitBaffles? I am not using blockmesh. So once I have faces and patches set, how to I name the face set for the dictionary and then merge?

Thank you.
Sylvia
sjs is offline   Reply With Quote

Old   August 6, 2008, 21:56
Default Ok, I was going down a wrong p
  #4
sjs
New Member
 
Sylvia Smullin
Join Date: Mar 2009
Posts: 10
Rep Power: 8
sjs is on a distinguished road
Ok, I was going down a wrong path with the faceSetDict -- turns out I didn't need that all. And then what was holding me up on the merging is that I needed to have faces defined by points of the same number (instead of points with different numbers but in the same location) to be recognized as duplicate. Thank you for the pointer.

Sylvia
sjs 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
Kutta and wake conditions over an airfoil Laith Mohammed Main CFD Forum 1 September 29, 2009 04:59
Burgerbs equation non constant Boundary Conditions Initial Conditions arkangel OpenFOAM Running, Solving & CFD 1 October 2, 2008 14:48
Boundary conditions for turbulent boundary layer Thomas FLUENT 1 June 17, 2008 05:14
wake centerline length &wake length Fred Main CFD Forum 0 July 27, 2007 01:20
Integral boundary conditions turbulent intensitylength boundary conditions olesen OpenFOAM Running, Solving & CFD 0 July 27, 2006 07:18


All times are GMT -4. The time now is 09:06.