Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted:
1 decade ago
Jan 30, 2011, 4:22 a.m. EST
Hi
when you pass th "FINISH" flag in the geometrical section you perform the equivalent of the 3.5 internal geomanalyze() operator.
In FINISH UNION mode, all geometrical OBJECTS are transformed into FEM geometric ELEMENTS.
Elemets are numbered, unique, defined into "Domains", "Boundaries" possibly "Edges" and "Points" all depending on the 3D, 2D, 1D... geometry selected.
So if you have a line upon an edge of a 2D geometry, COMSOL wil "unite" them and as they overlap they are made unique. Therefore you normally do not need to "add this second line" you can select the edge (boundary) for each physics.
Now, in certain cases you need to have separate, but overlapping, domains or boundaries. This you can obtain with the "FINSIH ASSEMBLY" mode. Then different ways are used and overlapping domains and boundaries might coexist. The corollary is that you need to efine PAIRS and do all cupling of the duplicated entities.
But to go into details it's all too long to write out here, the best is to take one of the COMSOL courses.
I hope with this you can exercice it to learn the subtil differences
--
Good luck
Ivar
Hi
when you pass th "FINISH" flag in the geometrical section you perform the equivalent of the 3.5 internal geomanalyze() operator.
In FINISH UNION mode, all geometrical OBJECTS are transformed into FEM geometric ELEMENTS.
Elemets are numbered, unique, defined into "Domains", "Boundaries" possibly "Edges" and "Points" all depending on the 3D, 2D, 1D... geometry selected.
So if you have a line upon an edge of a 2D geometry, COMSOL wil "unite" them and as they overlap they are made unique. Therefore you normally do not need to "add this second line" you can select the edge (boundary) for each physics.
Now, in certain cases you need to have separate, but overlapping, domains or boundaries. This you can obtain with the "FINSIH ASSEMBLY" mode. Then different ways are used and overlapping domains and boundaries might coexist. The corollary is that you need to efine PAIRS and do all cupling of the duplicated entities.
But to go into details it's all too long to write out here, the best is to take one of the COMSOL courses.
I hope with this you can exercice it to learn the subtil differences
--
Good luck
Ivar