Cyclic BC on side walls

thomas99 · February 9, 2012, 06:35

Hi All,

I'm presently attempting to simulate flow over an object in a parallel plate channel in 3D by using a cyclic boundary conditions. To make this a little more understood, the geometry is as such: an inlet, an outlet, top/bottom walls, and for the sides instead of specifying symmetry or a wall, I put cyclic. The problem is when I try to run a case in pisoFoam I get floating point errors. If anyone has experience with this or can point me to a thread where this has been discussed (I couldn't really find an answer in the other threads) that would really help.

Tom

linnemann · February 9, 2012, 08:34

Hi

It would help if you wrote how you create the cyclic boundary and post the output from the solver and attach as a log file.

Also is it rotational cyclic or translate cyclic?

thomas99 · February 9, 2012, 09:38

Hi,

Thanks for replying to my thread. Your request for the method of creating my mesh caused me to examine this issue more carefully. I used createPatch to create translational periodicity and it turns out I had incorrectly understood the behavior of the separation vector. I specified the separation vector correctly and am getting now good results. Anyway sorry for posting something that turned out so trivial.

Regards,
Tom

February 9, 2012, 06:35	Cyclic BC on side walls	#1
thomas99 New Member Tom Witten Join Date: May 2011 Location: Freiberg Posts: 10 Rep Power: 16	Hi All, I'm presently attempting to simulate flow over an object in a parallel plate channel in 3D by using a cyclic boundary conditions. To make this a little more understood, the geometry is as such: an inlet, an outlet, top/bottom walls, and for the sides instead of specifying symmetry or a wall, I put cyclic. The problem is when I try to run a case in pisoFoam I get floating point errors. If anyone has experience with this or can point me to a thread where this has been discussed (I couldn't really find an answer in the other threads) that would really help. Tom

February 9, 2012, 08:34		#2
linnemann Senior Member Niels Nielsen Join Date: Mar 2009 Location: NJ - Denmark Posts: 556 Rep Power: 28	Hi It would help if you wrote how you create the cyclic boundary and post the output from the solver and attach as a log file. Also is it rotational cyclic or translate cyclic? __________________ Linnemann PS. I do not do personal support, so please post in the forums.

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February 9, 2012, 09:38		#3
thomas99 New Member Tom Witten Join Date: May 2011 Location: Freiberg Posts: 10 Rep Power: 16	Hi, Thanks for replying to my thread. Your request for the method of creating my mesh caused me to examine this issue more carefully. I used createPatch to create translational periodicity and it turns out I had incorrectly understood the behavior of the separation vector. I specified the separation vector correctly and am getting now good results. Anyway sorry for posting something that turned out so trivial. Regards, Tom