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how to calculate the integration of any section in comsol 3.5

Posted Dec 11, 2010, 5:50 a.m. EST Version 3.5a 5 Replies

Thanh Long Vu
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Hi all,
Some one help me how to calculate the integration of any section in comsol 3.5, because i see in comsol it calculate only the boundary integration. How can i do that with any boundary integration?
Thanks so much

Long
5 Replies Last Post Dec 13, 2010, 4:10 p.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Dec 12, 2010, 3:12 a.m. EST
Hi

the easiest is to make an internal boundary (with default continuity BC conditions) and integrate on this internal boundary within 3.5a GUI's.
If not, I tend to remember that in V3.5a you must go via matlab to interpolate the results on a virtual cut-plane and integrate thereon.
In V4 you can extract a subset of your solution defined on a cut plane and perform operations thereon

--
Good luck
Ivar
Hi the easiest is to make an internal boundary (with default continuity BC conditions) and integrate on this internal boundary within 3.5a GUI's. If not, I tend to remember that in V3.5a you must go via matlab to interpolate the results on a virtual cut-plane and integrate thereon. In V4 you can extract a subset of your solution defined on a cut plane and perform operations thereon -- Good luck Ivar
Thanh Long Vu
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Posted: 1 decade ago Dec 13, 2010, 3:01 a.m. EST
Hi Ivar,
Thanks for your answer but i have no comsol v4, just v3.5a so i don't know to make an internal boundary from comsol, can u explain more detail for me please. If not, go via matlab to interpolate the results on a virtual cut-plane and integrate thereon like that i use the function "postint" in comsol with matlab?

Long
Hi Ivar, Thanks for your answer but i have no comsol v4, just v3.5a so i don't know to make an internal boundary from comsol, can u explain more detail for me please. If not, go via matlab to interpolate the results on a virtual cut-plane and integrate thereon like that i use the function "postint" in comsol with matlab? Long
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Dec 13, 2010, 5:12 a.m. EST
Hi

in 3.5/3.5a (as for 4) you can always cut your volume (CAD or geometry sections). These internal boundaries can then also be used for metrology (integration over edges, surfaces ...) with little extra RAm and sovler complexity costs

And indeed, in matlab, it's via the postinterp() you can extract the interpolated values over a ficitf boundary

--
Good luck
Ivar
Hi in 3.5/3.5a (as for 4) you can always cut your volume (CAD or geometry sections). These internal boundaries can then also be used for metrology (integration over edges, surfaces ...) with little extra RAm and sovler complexity costs And indeed, in matlab, it's via the postinterp() you can extract the interpolated values over a ficitf boundary -- Good luck Ivar
Thanh Long Vu
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Posted: 1 decade ago Dec 13, 2010, 8:52 a.m. EST
Hi,
Now i understand to calculate the boundary integration (edges, surfaces...) but i don't know how to cut the volume to make internal boundary. For example, i have a cube, now i want to make the middle internal surface in the cube, but i can't cut it by the plane. Can u show me these steps to make it?
Thanks so much

Long
Hi, Now i understand to calculate the boundary integration (edges, surfaces...) but i don't know how to cut the volume to make internal boundary. For example, i have a cube, now i want to make the middle internal surface in the cube, but i can't cut it by the plane. Can u show me these steps to make it? Thanks so much Long
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Dec 13, 2010, 4:10 p.m. EST
Hi

you have the union/intersection ... operations on the geoemtry.

If you have a cube and want to split it in the middle, create another rectangular block that is half the volume of the first one, as they overlap, when they are "analysed" (the moment COMSOL redefines the input geoemtry (objects a la v4) and form entities out of them (entities are (sub) volumes whch are unique, ordered and identified)) you will have two "half" cubes with aa common interiour boundary by default

--
Good luck
Ivar
Hi you have the union/intersection ... operations on the geoemtry. If you have a cube and want to split it in the middle, create another rectangular block that is half the volume of the first one, as they overlap, when they are "analysed" (the moment COMSOL redefines the input geoemtry (objects a la v4) and form entities out of them (entities are (sub) volumes whch are unique, ordered and identified)) you will have two "half" cubes with aa common interiour boundary by default -- Good luck Ivar

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