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-   -   Cylindrical coordinates (http://www.cfd-online.com/Forums/openfoam-pre-processing/62261-cylindrical-coordinates.html)

 amelia October 18, 2005 00:59

Hi, Since I have a flow in

Hi,

Since I have a flow in a cylindrical system, I would like to know if it is possible to introduce, in FOAM, the equations in cylindrical coordinates. Has anyone done this?

 hjasak October 18, 2005 11:00

This will not come naturally -

This will not come naturally - FOAM is set up to handle the cylindrical coordinates by creating a wedge geometry.

If you insist on writing your own equations in the cylindrical coordinate system, you will need to make a flat 2-D geometry and add the additional terms for the coordinate transformation into the cylindrical system. Does not sound too bad, but I am not aware of anyone who has actually done it.

Good luck,

Hrv

 mohanamuraly May 17, 2009 14:36

one question regarding the wege used in cylindrical coordinates. when the azimutal resolution is increased to say a degree then we would end up having highly skewed cells at the center. How reliable are the results in that case and how about numerical stabilty issues. I am trying to use cylindrical meshes but this problem cropped up in my mind.

 Prash April 13, 2011 11:51

Dear people,

I am little new to OpenFOAM, I am looking to create a cylindrical geometry in OpenFOAM, I dont think its in capability of BlockMeshDict to produce and discretize Cylindrical geometry.

Need Help :)

Prashant

Quote:
 Originally Posted by hjasak (Post 192184) This will not come naturally - FOAM is set up to handle the cylindrical coordinates by creating a wedge geometry. If you insist on writing your own equations in the cylindrical coordinate system, you will need to make a flat 2-D geometry and add the additional terms for the coordinate transformation into the cylindrical system. Does not sound too bad, but I am not aware of anyone who has actually done it. Good luck, Hrv

 mohanamuraly April 14, 2011 23:25

I have tried using OF for cylindrical grids. There are issues with numerical stability at the centerline. You can read more about it in my thesis

http://etda.libraries.psu.edu/ETD-db...rieve?etd=4445

I have combined the skewed wedge cells into one single prismatic poly cell. This way I could smooth out the numerical oscillations at the centerline and bring some stability (the oscillations do exist but are minimum and do not grow).

I tried the problem first in OF but decided to more away and write my own due to design constraints.

If you don't have the centerline as part of the computational domain (say) you have a body at the centerline then it should be ok ... otherwise !!! USE CYLINDRICAL GRIDS WITH CAUTION !!!

 skynet4ever January 8, 2012 09:22

Hi mohanamuraly,

I am very much interested in your Thesis. Unfortunately the link you posted is dead. I would be very nice if you could upload it otherwise. I will also send you a mail with my contact information. Thx

 yhaomin2007 December 25, 2012 23:42

You can try to use the MakeAxialMesh utility in OF wiki to convert axial mesh from 2D planar mesh

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