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mapped meshing

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Hi guys,

I have a simple geometry in 3D consisting mostly of rectangular elements (please see the attached model). I was wondering if its possible to mesh it via simple mapped mesh. This is essential otherwise default tetrahedral mesh generates enormous no. of mesh elements then it just takes forever to run the simulation.

I am working with version 4.2.

Thanks in advance for your help!


1 Reply Last Post Jun 1, 2012, 2:02 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Jun 1, 2012, 2:02 a.m. EDT
Hi

sweeping will not work like that because the topology of the middle part is different on source and destination faces.

But what you can do is to add a "thk" layer on the top and bottom of your fist block (in fact you have them already but as extra lower layers) and then Extrude for both cases all through the block + above as now. You will get many volumes inside each other but that will be sorted out by COMSOL into unique domains.
The difficulty afterwise is to group the different domains into the differnt material blocks, as you cut up your "logical" domains into smaller parts.

Then you can mesh the top surface and sweep yuor way down (or up) in the z direction more easily.

Anyhow if you want to get some useful results which such thin layers on a thick block (1:1000 ratio) you need at least 5 elements in the thickness of your thin layers, whcih puts also a rather poor mesh quality (but not necesarily catastrophic) except if you have a few Tb of RAM available and time to wait ....

Personally I would also suggest to consider the "surface thin film physics" BC nodes that allows you to replace a physical "thin" layer by "just" a surface mesh and some physics

By the way to better visualise the thin items you can add a Definition View and in this new view remove the "preserve aspect ratio tick (Camera sub node), then rezoom.

my example is 4.2a patched
--
Good luck
Ivar
Hi sweeping will not work like that because the topology of the middle part is different on source and destination faces. But what you can do is to add a "thk" layer on the top and bottom of your fist block (in fact you have them already but as extra lower layers) and then Extrude for both cases all through the block + above as now. You will get many volumes inside each other but that will be sorted out by COMSOL into unique domains. The difficulty afterwise is to group the different domains into the differnt material blocks, as you cut up your "logical" domains into smaller parts. Then you can mesh the top surface and sweep yuor way down (or up) in the z direction more easily. Anyhow if you want to get some useful results which such thin layers on a thick block (1:1000 ratio) you need at least 5 elements in the thickness of your thin layers, whcih puts also a rather poor mesh quality (but not necesarily catastrophic) except if you have a few Tb of RAM available and time to wait .... Personally I would also suggest to consider the "surface thin film physics" BC nodes that allows you to replace a physical "thin" layer by "just" a surface mesh and some physics By the way to better visualise the thin items you can add a Definition View and in this new view remove the "preserve aspect ratio tick (Camera sub node), then rezoom. my example is 4.2a patched -- Good luck Ivar

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