CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Pre-Processing

Symmetryplane, cyclic and wedge boundary conditions

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

Like Tree2Likes
  • 2 Post By Gerhard

LinkBack Thread Tools Search this Thread Display Modes
Old   November 3, 2011, 07:11
Question Symmetryplane, cyclic and wedge boundary conditions
New Member
Join Date: Sep 2011
Location: Norway
Posts: 8
Rep Power: 9
Taltan is on a distinguished road
I am a bit confused as to what the difference between these boundary conditions are. Any help would be appreciated. My take on these BC's:

1) SymmetryPlane
Mirrors along a plane so to reduce the amount of cells needed for a full model. For instance you have a model of a car, then you would only need to compute half of the car as the other half is symmetric.
2) Cyclic
Looping back information from one bc to another. For instance a pipe, where the outlet loops back to the inlet.
3) Wedge
This is the one I am the least confident about. Apparently this is only for 2D simulations for axisymmetric problems, for instance a pipe. But I though (hoped) that it was a way to reduce amount of cells in an axisymmetric 3D problem where you would only need to model a fraction of the pipe.
In the case I am working on I have a pipe which is axisymmetric with about 4 million cells and I wish to reduce this amount. Intuitively the wedge approach seemed good as I would only need the mesh for a small section of the pipe. However if this is only for 2D then my simulation would probably fall apart as I intend to model LES.

So hopefully the symmetryPlane approach would work in my case perhaps? Where I would revolve my pipe only 180 degrees and use symmetryPlane bc on the resulting flat surface.
Taltan is offline   Reply With Quote

Old   February 7, 2018, 06:24
Default BCs
New Member
Join Date: Mar 2017
Posts: 8
Rep Power: 4
Gerhard is on a distinguished road
Hi Taltan

Be careful of these boundary conditions. They should be used with great care. The symmetry example you gave will only work if the flow is laminar. If it is not, there would be vortices behind the car, which is not symmetrical any more. But the mirror explanation is correct.

The wedge BC is to reduce a 3D case to a 2D case... If the flow is axisymmetric, thus f(r,z), then you should be able to use this boundary condition (not sure about the LES thing).

The symmetry approach might also work and you only need to revolve the pipe by 90 degrees if you think about it
Swift and sankalpjain like this.
Gerhard is offline   Reply With Quote

Old   April 16, 2018, 08:38
Gautami Erukulla
Join Date: Mar 2009
Posts: 71
Rep Power: 12
gautami is on a distinguished road
Dear All,

1. To simulate a floating cylinder (using 6DOF rigid body motion solver) with symmetryPlane option, dividing the computational domain into half, does the mass and moment of inertia of cylinder defined in the dynamicMeshDict be divided to half. Taking full mass sinks the cylinder.
2. To simulate a floating cylinder (using 6DOF rigid body motion solver) with 3 DOF motion in heave, surge and pitch, and be restrained with linear spring, should the spring stiffness be taken half value for half the domain using symmetry plane option.
Kindly please advise. Thank You.

Gautami Erukulla.
gautami is offline   Reply With Quote

Old   February 12, 2019, 02:13
Senior Member
Join Date: Mar 2009
Posts: 197
Rep Power: 12
quarkz is on a distinguished road

I have a similar problem involving flow past a cone. I intent to run it as a LES simulation. I am now using 1/4 (90deg rotation) of the cone with the 2 planes using the symmtryplane BC.

Btw, is it possible to reduce further to something of a wedge shape (30 or 45deg rotation) while using the same BC? This would save the computation even further.

quarkz is offline   Reply With Quote

Old   May 9, 2019, 07:08
Default Wedge angle.
New Member
Sri harsha Revu
Join Date: Apr 2019
Posts: 4
Rep Power: 2
hasha is on a distinguished road
Hi quarkz,
Wedge angle shouldn't exceed 5deg in the axis symmetric problems of OpenFOAM.
hasha is offline   Reply With Quote


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 On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Overriding Wedge Symmetry and Cyclic BC for a single field diegon OpenFOAM Running, Solving & CFD 1 December 2, 2014 00:45
can I use cyclic boundary condition to modeling axisymmetric flow ? mechy OpenFOAM 0 July 8, 2011 14:16
simpleSRFoam, makePatch and cyclic patch vaina74 OpenFOAM Running, Solving & CFD 7 February 28, 2011 07:26
Axi-symmetric case gives wrong answer pbryant OpenFOAM Bugs 1 February 14, 2011 21:17
[blockMesh] Cyclic command Panagioto OpenFOAM Meshing & Mesh Conversion 1 May 20, 2010 11:39

All times are GMT -4. The time now is 03:21.