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About geometry coincident
Posted 29.01.2011, 13:02 GMT-5 Geometry Version 4.0 1 Reply
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First, I draw a rectangle, then I draw a line which is coincident with one of the sides of the rectangle. However, I cannot find the line, does comsol regard the two lines as a single line by default?
1 Reply Last Post 30.01.2011, 04:22 GMT-5
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Posted:
1 decade ago
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
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