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What material is present by default in a hollow space?

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Assume that I have a large acrylic block. Now, I machine a small circle in the center upto half way in the acrylic. Then I place an eleastic membrane on top of the acrylic such that the hole inside is filled with air.

When I try to model this, I m not able to specify air in the hollow place as it is not considered to be a domain. How can I model this? Does comsol assume air to be present in the hollow space by default or a vacuum or what??

Thank you.


2 Replies Last Post 2018年5月11日 GMT-4 02:20

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Posted: 6 years ago 2018年5月1日 GMT-4 14:25

If that empty space is not a domain, COMSOL does not consider it at all in the model; no material is assigned to it, and it will not be meshed. You need to actually make a domain in the geometry and set the material as air.

This is also important if you have two objects in space and you want to calculate their interaction (via electric or magnetic fields for example), you need to make an air domain in the geometry that surrounds the two objects. If you don't, comsol will solve the model in the objects, but not in the space between them, yielding unphysical results.

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-- Louis Haeberle
MSc Student (Physics)
Silicon Spintronics Research Group (Pr. Pioro-Ladrière)
Université de Sherbrooke
If that empty space is not a domain, COMSOL does not consider it at all in the model; no material is assigned to it, and it will not be meshed. You need to actually make a domain in the geometry and set the material as air. This is also important if you have two objects in space and you want to calculate their interaction (via electric or magnetic fields for example), you need to make an air domain in the geometry that surrounds the two objects. If you don't, comsol will solve the model in the objects, but not in the space between them, yielding unphysical results.

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Posted: 6 years ago 2018年5月11日 GMT-4 02:20

How to set the empty space as a domain?

How to set the empty space as a domain?

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