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Inverted mesh near coordinates with boundary layer mesh
Posted 21 apr 2010, 11:52 GMT-4 3 Replies
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In my test model, I used boundary layer mesh to solve a navier-stokes + convection-diffusion problem. But I get such error from beginning. Any ideas?
3 Replies Last Post 21 apr 2010, 16:46 GMT-4
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Posted:
1 decade ago
Hi
"Inverted mesh" means that the mesh quality is so low that when the parts/mesh deforms the higher order element functions used ends up inverting the topology representation of the element (it becomes inside-out). Thereofre the warning taht COMSOL uses linear elements, hat allows to continue to get some results, but with lower quality.
So either your starting mesh is "bad" (check the mesh statistics and plot the mesh quality) and it does not allow to survive with the deformations, or you ahve i.e. an ALE application with (too) large displacements. CMSOL organises a full day couse on ALE and meshing, and it's not really a lot, taking into account all the possibilities and things to consider.
When you use boundary meshes the mes density is very high and often their shape is inhomogenous (i.e. long and thin" therefore I'm not astonished that for larger deformations, one get easily problems in these regions
Good luck
Ivar
"Inverted mesh" means that the mesh quality is so low that when the parts/mesh deforms the higher order element functions used ends up inverting the topology representation of the element (it becomes inside-out). Thereofre the warning taht COMSOL uses linear elements, hat allows to continue to get some results, but with lower quality.
So either your starting mesh is "bad" (check the mesh statistics and plot the mesh quality) and it does not allow to survive with the deformations, or you ahve i.e. an ALE application with (too) large displacements. CMSOL organises a full day couse on ALE and meshing, and it's not really a lot, taking into account all the possibilities and things to consider.
When you use boundary meshes the mes density is very high and often their shape is inhomogenous (i.e. long and thin" therefore I'm not astonished that for larger deformations, one get easily problems in these regions
Good luck
Ivar
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Posted:
1 decade ago
Thank you Ivar. Indeed, it is as you said. However, I am solving N-S and C-D, so no movement still. I will check your initial mesh suggestion anyway.
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Posted:
1 decade ago
Hi
Then check carefully your geometry, you might have some small features that are badly meshed, if its a CAD geometry, you could run the defeaturing/repair analysis (it should be under "draw" I beleive, I'm at home no Comsol here to check;)
Good luck
Ivar
Then check carefully your geometry, you might have some small features that are badly meshed, if its a CAD geometry, you could run the defeaturing/repair analysis (it should be under "draw" I beleive, I'm at home no Comsol here to check;)
Good luck
Ivar