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Meshing Air

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I'm new to 3D COMSOL and I have the geometry for a chamber that will have air running through it while it performs its function. I am easily able to mesh the geometry, but I'm having problems finding a way to mesh the "air zone." I want the geometry and the air zone to have separate meshes so that I can have a very fine mesh for the air and a less fine mesh for the geometry which will only be transferring heat. What steps are needed to make the air mesh, and how can I make it so that the air mesh and the geometry mesh are separately meshable entities?

5 Replies Last Post 20 déc. 2012, 15:10 UTC−5
Nagi Elabbasi Facebook Reality Labs

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Posted: 1 decade ago 19 déc. 2012, 10:18 UTC−5
Change the final Geometry node setting to “Form an Assembly”. That way even though the part and the air geometries are adjacent they will remain separate and you can mesh them independently. With assemblies you should also use Identity Pairs (or Contact Pairs) to let COMSOL know which boundaries are linked. COMSOL by default will create these pairs for you.

Nagi Elabbasi
Veryst Engineering
Change the final Geometry node setting to “Form an Assembly”. That way even though the part and the air geometries are adjacent they will remain separate and you can mesh them independently. With assemblies you should also use Identity Pairs (or Contact Pairs) to let COMSOL know which boundaries are linked. COMSOL by default will create these pairs for you. Nagi Elabbasi Veryst Engineering

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Posted: 1 decade ago 19 déc. 2012, 10:36 UTC−5
Thanks Nagi,

I don't actually have an air domain right now, and I don't know how to make one. Right now, I have a geometry that has an apparent but unincorporated entrance and exit for the air flow, but I don't have a domain for the air. How can I make the air domain?

Thomas Brooks
Thanks Nagi, I don't actually have an air domain right now, and I don't know how to make one. Right now, I have a geometry that has an apparent but unincorporated entrance and exit for the air flow, but I don't have a domain for the air. How can I make the air domain? Thomas Brooks

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Posted: 1 decade ago 19 déc. 2012, 13:51 UTC−5
The thing is, the CAD that I imported is an unusual shape so I can't just draw a geometry that is the air. I need to be able to somehow define the boundaries of the whole system and make COMSOL assume the volume that is currently unoccupied by my CAD needs to be occupied by a new domain that I will give air properties to.
The thing is, the CAD that I imported is an unusual shape so I can't just draw a geometry that is the air. I need to be able to somehow define the boundaries of the whole system and make COMSOL assume the volume that is currently unoccupied by my CAD needs to be occupied by a new domain that I will give air properties to.

Jeff Hiller COMSOL Employee

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Posted: 1 decade ago 19 déc. 2012, 14:34 UTC−5
See www.comsol.com/community/forums/general/thread/32396/
See http://www.comsol.com/community/forums/general/thread/32396/

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Posted: 1 decade ago 20 déc. 2012, 15:10 UTC−5
Thanks guys, and for the record for anyone who wanders upon this thread: I got it working by using "cap faces," selecting every curve on the boundaries (the inlet and outlet) of the air flow region and then using "form union" with finalization method set to "Form a union"
Thanks guys, and for the record for anyone who wanders upon this thread: I got it working by using "cap faces," selecting every curve on the boundaries (the inlet and outlet) of the air flow region and then using "form union" with finalization method set to "Form a union"

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