values on a slip boundary

Moslem · January 9, 2015, 10:20

Hi,
I want to use the slip boundary condition for some domain boundaries in a CFD solution. I need to know the velocity vectors on those boundaries. unfortunately OF does not report them in the data files and specifies the slip boundaries like this:
.
.
.
upperWall
{
type slip;
}
lowerWall
{
type slip;
}
.
.
.

How can I force the OF to report the velocity vectors ?
Thanks in advance.
p.s. The same problem exists using the symmetryPlane boundary condition.

nimasam · January 10, 2015, 04:25

Dear your question is vague, if you want to see velocity vector, you can use parafoam, choose the patch you like

Moslem · January 10, 2015, 05:07

I want the OF to report the "numerical" values of velocity vectors exactly on the boundary. OF just defines the whole boundary as "slip". I cannot find what is the velocity vector on each face element. I want to present the boundary values, e.g. tangential velocity, on a graph.

nimasam · January 10, 2015, 05:14

So my pervious method, should work for you.

Moslem · January 10, 2015, 05:33

Thanks,
Yes, it works. But, I'm not sure if they are the exact values obtained in the simulation. It seems that the postprocessing softwares (Paraview and Tecplot) calculate these boundary values by some kind of inter/extrapolation methods. As an evidence, this method does not yield zero values for the normal velocity on a slip (or symmetry) boundary.

January 9, 2015, 10:20	values on a slip boundary	#1
Moslem New Member M. Sabouri Join Date: Nov 2011 Posts: 24 Rep Power: 15	Hi, I want to use the slip boundary condition for some domain boundaries in a CFD solution. I need to know the velocity vectors on those boundaries. unfortunately OF does not report them in the data files and specifies the slip boundaries like this: . . . upperWall { type slip; } lowerWall { type slip; } . . . How can I force the OF to report the velocity vectors ? Thanks in advance. p.s. The same problem exists using the symmetryPlane boundary condition.

January 10, 2015, 04:25		#2
nimasam Senior Member Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,267 Blog Entries: 1 Rep Power: 25	Dear your question is vague, if you want to see velocity vector, you can use parafoam, choose the patch you like __________________ My Personal Website (http://nimasamkhaniani.ir/) Telegram channel (https://t.me/cfd_foam)

January 10, 2015, 05:14		#4
nimasam Senior Member Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,267 Blog Entries: 1 Rep Power: 25	So my pervious method, should work for you. __________________ My Personal Website (http://nimasamkhaniani.ir/) Telegram channel (https://t.me/cfd_foam)

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January 10, 2015, 05:07		#3
Moslem New Member M. Sabouri Join Date: Nov 2011 Posts: 24 Rep Power: 15	I want the OF to report the "numerical" values of velocity vectors exactly on the boundary. OF just defines the whole boundary as "slip". I cannot find what is the velocity vector on each face element. I want to present the boundary values, e.g. tangential velocity, on a graph.

January 10, 2015, 05:33		#5
Moslem New Member M. Sabouri Join Date: Nov 2011 Posts: 24 Rep Power: 15	Thanks, Yes, it works. But, I'm not sure if they are the exact values obtained in the simulation. It seems that the postprocessing softwares (Paraview and Tecplot) calculate these boundary values by some kind of inter/extrapolation methods. As an evidence, this method does not yield zero values for the normal velocity on a slip (or symmetry) boundary.