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Problems with swept mesh

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Hello,

I have a cylindrical 3D domain, with an inlet hole (from which water comes in to the domain). I would like to create an axis-symmetric mesh in my domain but not too sure how I could do this. So far I've only been able to use mesh with free tetrahedral. But for my problem I would need an axis-symmetric mesh if possible.

I have tried a mapped and swept mesh, but I always get an error saying "unsupported topology domain" or "degenerate element was found": What I am doing is mapping the bottom lid of the cylinder (where the inlet is, however comsol does not allow me to map inside the inlet domain as the faces do not have 4 edges). So inside the inlet area I have used a free quad mesh. I attach a photo of this bottom lid once it's been meshed. Then I try to sweep this mesh up to the top lid of the cylinder (where there is no inlet) but this does not work (I'm also attaching an image of the whole cylinder)

I would be very grateful if someone could give me some ideas of why this is not working, or maybe come up with another way of creating an axis-symmetric mesh.

Thank you very much,

Nadia





2 Replies Last Post 17.04.2012, 11:42 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 17.04.2012, 11:02 GMT-4
Hi

in 3.5 you had "revolve" mesh feature in 3D, It seems that its not impleemnted in V4 (not yet only, I hope), but in v4.2a they have introduced the advanced copy and copy and mirror, scale ... functionality for the mesh.

Furthermore, sweep mesh has a limitation: your geometry, along the sweep direction, must not change topology (no appearance of BC edges or points. The only way around is to cut your sweep domain along any of such topology changes

I know that in 3.5 the 2D-axi geoemtry could not accept mapped meshes along the axis of symmetry, one had to convert the first layer to tri, this was for r=0 singularitiy issues, w.r.t. the equations used. I'm not sure if this is still the case in V4, and how it might apply also for 3D.

I would suggest that you ask "support" for such a case, and pls report bak it's of general interest ;)

--
Good luck
Ivar
Hi in 3.5 you had "revolve" mesh feature in 3D, It seems that its not impleemnted in V4 (not yet only, I hope), but in v4.2a they have introduced the advanced copy and copy and mirror, scale ... functionality for the mesh. Furthermore, sweep mesh has a limitation: your geometry, along the sweep direction, must not change topology (no appearance of BC edges or points. The only way around is to cut your sweep domain along any of such topology changes I know that in 3.5 the 2D-axi geoemtry could not accept mapped meshes along the axis of symmetry, one had to convert the first layer to tri, this was for r=0 singularitiy issues, w.r.t. the equations used. I'm not sure if this is still the case in V4, and how it might apply also for 3D. I would suggest that you ask "support" for such a case, and pls report bak it's of general interest ;) -- Good luck Ivar

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Posted: 1 decade ago 17.04.2012, 11:42 GMT-4
Hi Ivar,

Thanks for your reply and ideas, I'll play around with the copy, and mirror options... maybe this way I could set up an axis-symmetric mesh.

I will report back when I get an answer from support.

Best wishes,

Nadia
Hi Ivar, Thanks for your reply and ideas, I'll play around with the copy, and mirror options... maybe this way I could set up an axis-symmetric mesh. I will report back when I get an answer from support. Best wishes, Nadia

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