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-   -   zero boundary condition on the axis. (http://www.cfd-online.com/Forums/openfoam/77879-zero-boundary-condition-axis.html)

 universez July 6, 2010 16:06

zero boundary condition on the axis.

Hi,
I want to use Openfoam to model a cylindrical problem. I am using a 5 degree pie shape mesh with two wedge on the front and back and one
symmetryPlane at the Axis.

I have a vector field A, My question is how can i define boundary condition on the Axis as zero?

Thanks,

Yu

 sega July 7, 2010 02:20

Quote:
 Originally Posted by universez (Post 266031) I have a vector field A, My question is how can i define boundary condition on the Axis as zero?
On the (symmetry?) axis you don't have any boundary conditions because there is no patch you can impose some.

As a matter of fact there will be a zeroGradient on the axis as this is a symmetry axis.

 marcbest July 7, 2010 03:47

so you can write for each boundary condition:

Axis //name of the axis-patch
{
type symmetryPlane;
}

_____

I don't kow if it is possible to make the Cylinder with a "bore hole" through the middle axis and then define the resulting tiny patch as zero if this is really necessary for your case...

 noramat July 13, 2010 15:47

question to wedge-type

hello, i also have a question to wedge-type..

why it is possible to have exactly 5 degree for wedge-type? Are there more inaccuracies in the solutions when using more degrees?

thanks a lot..

noramat

 maddalena July 14, 2010 06:16

Hello (one more time ;))...
Quote:
 Originally Posted by noramat (Post 267111) why it is possible to have exactly 5 degree for wedge-type? Are there more inaccuracies in the solutions when using more degrees?
Similar questions have already been posted here and replied by hrvoje. On that page there are also some more hints on creating a wedge.
enjoy!