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Selection of interior boundaries

Leonardo Mechanical Engineering

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Hello, I have been working with the "Moisture Transport in Building Materials" module and I would like to add a "Moisture Content" node in the boundary (a line) shared by two 2D domains. The problem is that the "Moisture Content" node does not let me select any of the interior boundaries, it seems to only allow the selection of the outer ones. Does anyone know how to make the interior boundaries selectable? Any information on this subject would be very appreciated!

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Kind regards,
Leonardo

2 Replies Last Post Oct 5, 2021, 4:31 p.m. EDT
Jeff Hiller COMSOL Employee

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Posted: 3 years ago Sep 29, 2021, 2:52 p.m. EDT
Updated: 3 years ago Sep 29, 2021, 4:00 p.m. EDT

Hello Leonardo,

One approach is to replace the line with a very narrow rectangular slit that you remove from the computational domain; then you have exterior boundaries and you can apply the "Moisture Content" boundary condition, It's not a very elegant approach and it may have the unwanted effect of causing the mesh to become unnecessarily fine at the ends of the slit.

A second, more elegant aproach which does not affect the mesh consists in using a Weak Constraint condition, as illustrated in the attached toy model.

Best,

Jeff

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Jeff Hiller
Hello Leonardo, One approach is to replace the line with a very narrow rectangular slit that you remove from the computational domain; then you have exterior boundaries and you can apply the "Moisture Content" boundary condition, It's not a very elegant approach and it may have the unwanted effect of causing the mesh to become unnecessarily fine at the ends of the slit. A second, more elegant aproach which does not affect the mesh consists in using a Weak Constraint condition, as illustrated in the attached toy model. Best, Jeff


Leonardo Mechanical Engineering

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Posted: 3 years ago Oct 5, 2021, 4:31 p.m. EDT

Hello Jeff, Thaks a lot for the answer, it was very clear and useful!

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Kind regards,
Leonardo
Hello Jeff, Thaks a lot for the answer, it was very clear and useful!

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