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Different boundary temperatures

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Hi

I'm new to COMSOL.
I've created a square of larch (supposed to be a cross-section). I defined the material myself. I want to set the surface temperature on two of the edges to 293K, one edge 273K and final edge 323K. I seem to only be able to set the temperature for all boundries at once.
Please note the picture I've attached.
What to do?

Thanks in advance


2 Replies Last Post 15.06.2017, 12:45 GMT-4
Jeff Hiller COMSOL Employee

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Posted: 7 years ago 15.06.2017, 08:33 GMT-4
Updated: 7 years ago 16.06.2017, 08:16 GMT-4
Hello Josephine,
There are several ways of selecting or deselecting boundaries, including picking them with the mouse in the Graphics window.
As you mention that you are new to the software, I would encourage you to work through the "Introduction to COMSOL Multiphysics" manual. It will help you get familiar with the operation of the COMSOL Desktop in no time. You can find all manuals under File > Help > Documentation. The "Introduction to COMSOL Multiphysics" is also available from the COMSOL website: cdn.comsol.com/documentation/5.3.0.248/IntroductionToCOMSOLMultiphysics.pdf
Best,
Jeff
PS: Be aware that if two contiguous edges are at different temperatures, your problem will be singular at the point where they touch (See www.comsol.com/blogs/singularities-in-finite-element-models-dealing-with-red-spots/).
Hello Josephine, There are several ways of selecting or deselecting boundaries, including picking them with the mouse in the Graphics window. As you mention that you are new to the software, I would encourage you to work through the "Introduction to COMSOL Multiphysics" manual. It will help you get familiar with the operation of the COMSOL Desktop in no time. You can find all manuals under File > Help > Documentation. The "Introduction to COMSOL Multiphysics" is also available from the COMSOL website: https://cdn.comsol.com/documentation/5.3.0.248/IntroductionToCOMSOLMultiphysics.pdf Best, Jeff PS: Be aware that if two contiguous edges are at different temperatures, your problem will be singular at the point where they touch (See https://www.comsol.com/blogs/singularities-in-finite-element-models-dealing-with-red-spots/).

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Posted: 7 years ago 15.06.2017, 12:45 GMT-4
I think you can add a point in your boundary.
For instance, you add a point in the middle of upper side boundary. This way, your upper-side boundary will be divided into two boundaries (left-side of point and right-side of point)
I think you can add a point in your boundary. For instance, you add a point in the middle of upper side boundary. This way, your upper-side boundary will be divided into two boundaries (left-side of point and right-side of point)

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