Hello Timo,
I did not really get what you want to do. Do want to create a
rectangular domain in 2D, where the cylinder is excluded? Therefore the
function hyper_cube_with cylindrical_hole, which you already mentioned,
would be the right choice.
It is quite obvious that the function cylinder only exists in 3d, since
in 2d this is would be the same object as the function hyper_ball
creates, namely a circle.
However, I do not quite understand, why you want to merge two grids.
Perhabs you could describe your geometry in more detail.
Best Regards,
Markus
Am 13.07.11 15:10, schrieb Timo Koellner:
Hi everyone,
I'm trying to build a grid describing a cylinder in an rectangular
domain in 2D (cylinder infinitely spread in z-direction). I found the
cylinder and the hyper_cube_with_cylindrical_hole in GridGenerator as
well as the merge_triangulations function in developer version.
Regardless of the fact, that cylinder is only implemented in 3d as a
Cylinder, I see two problems:
1) The coarse meshes do have different levels of Cylinders. While the
coarse cylinder represents a rectangle, the cylindrical hole is a
octagon.
2) After merging, the information about the cylindrical boundary is
lost and is in fact an interior boundary (indicator = 255). So there's
no way to actually get an "real" cylinder on refinement, as the
cylinder emerging from the cylindrical hole will stay a octagon.
I tried solving the first problem by writing my own implementation of
a cylinder, which looks the same as the cylindrical hole. But doing so
there's a problem with the orientation of the boundary lines. (An
error occurred in line <1664> of file <deal.II/source/grid/tria.cc> in
function ...::create_triangulation(...))
Nontheless, there still would be the second problem. This one could
only be solved if it was possible to preserve boundary indicators on
merging, what should be possible by editing the merge_triangulations
function. But then I would have lines actually not being real
boundaries with an boundary indicator != 255. Is this a problem for
further calculation?
Anyone with some advise on how to do such a grid? Any other approaches
than the above on?
Thanks,
Timo
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