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Mesh generation for a thin layer

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Hi,
I am trying to generate meshes in a 2-D thin layer (1000 m by 0.01 m).
I tried many times using different predefined mesh size, but I failed.
How can I generate meshes?
Thanks.

3 Replies Last Post 22 giu 2010, 17:04 GMT-4

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Posted: 1 decade ago 14 apr 2010, 06:14 GMT-4
use shell model or try extrusion from a 2D draw
use shell model or try extrusion from a 2D draw

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 14 apr 2010, 06:54 GMT-4
Hi

try a search on the forum, there are a couple of earlier discussions in these items too

have fun Comsoling
Ivar
Hi try a search on the forum, there are a couple of earlier discussions in these items too have fun Comsoling Ivar

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Posted: 1 decade ago 22 giu 2010, 17:04 GMT-4
Hi Ivar, hi Youngmin.

i searched in the forum but sadly no thread was about thin layers and big scale differnces in deatil. I hope it is okay to go on with the dicussion here ... :)
(Sadly) we have to handle similar problems. We have a 3D (swimming pool) model with a thin (spillway) outlet boundary. The shape ratio is1:6E3 (spillway layer to longest boundary). In our case solving Navier-Stokes laminar flow had problems to converge. The reason is of cource the mesh quality. First of our ideas was to swap the thin spillway layer and mesh the remaining with freemesher. With this method the mesh size (and mesh quality) has huge gradients in the transition region from swaped- to freemesh.
It seems defining a scale factor for the freemesher (for your (thin layer) height-direction) helps to generate usefull meshes. Even without swapping the thin layer.
What also seems to work is to divide the geometry in several subdomains by using internal boundarys.
Respecting both scale factor ond subdomain-division helps also to preventing "Failed to insert point at ..." . Actually we still have no propper mesh working for us.

BTW: found this in the www. Maybe it helps. cds.comsol.com/access/dl/papers/1704/Holzbecher_pres.pdf

Do you have some more meshing-ideas that help to handle big scale gradients in one model?


Regards,

Bertram
Hi Ivar, hi Youngmin. i searched in the forum but sadly no thread was about thin layers and big scale differnces in deatil. I hope it is okay to go on with the dicussion here ... :) (Sadly) we have to handle similar problems. We have a 3D (swimming pool) model with a thin (spillway) outlet boundary. The shape ratio is1:6E3 (spillway layer to longest boundary). In our case solving Navier-Stokes laminar flow had problems to converge. The reason is of cource the mesh quality. First of our ideas was to swap the thin spillway layer and mesh the remaining with freemesher. With this method the mesh size (and mesh quality) has huge gradients in the transition region from swaped- to freemesh. It seems defining a scale factor for the freemesher (for your (thin layer) height-direction) helps to generate usefull meshes. Even without swapping the thin layer. What also seems to work is to divide the geometry in several subdomains by using internal boundarys. Respecting both scale factor ond subdomain-division helps also to preventing "Failed to insert point at ..." . Actually we still have no propper mesh working for us. BTW: found this in the www. Maybe it helps. http://cds.comsol.com/access/dl/papers/1704/Holzbecher_pres.pdf Do you have some more meshing-ideas that help to handle big scale gradients in one model? Regards, Bertram

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