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Get warnings "inverted mesh element near coordinates"

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Hi all,

I'm follow the guidance from Ivar to try to develop a simple structure with parameter of surface roughness. However I got the error "Inverted mesh element near coordinates". I have never seen this error before, and googled a little bit, and seems this error is related to "distorted mesh". Does anyone have some experience with this?

3 Replies Last Post Nov 12, 2014, 1:35 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Apr 14, 2010, 4:02 p.m. EDT
Hi

have you looked carefully at your mesh results to identify what is happening, it could be that you have locked to many DoF's of your moving mesh along the lateral sides.
Take a quick read about ALE in the doc, there are a few things that might help such as using linar displacements, to get the full mesh structure to follow in a more regular way, if you have large displacements w.r.t. the mesh size, you might get a too large deformation, hence "inverted elements"

Hope this helps on the way
Ivar
Hi have you looked carefully at your mesh results to identify what is happening, it could be that you have locked to many DoF's of your moving mesh along the lateral sides. Take a quick read about ALE in the doc, there are a few things that might help such as using linar displacements, to get the full mesh structure to follow in a more regular way, if you have large displacements w.r.t. the mesh size, you might get a too large deformation, hence "inverted elements" Hope this helps on the way Ivar

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Posted: 1 decade ago Jul 16, 2010, 12:58 p.m. EDT
Hi,

I want to do a 3D modelling of moving a particle by acoustic wave, throughout a microchannel. I could model by using Comsol 3.5a when the "solve" is stationary, but when I try to solve in transient mode, I got a warning as "inverted mesh element near coordinates". The coordinates are exactly placed in my particle location!! So, I think, this means that there is a problem in meshing process of my particle (because it is so tiny: around 2um in length, width, and heigth). However; the size of my mesh is so tiny (around 1/6 of the wavelength 40um).
I read the Comsol modeling guide for many times! But, I couldn't find what's wrong during my modelling?

Mr. Ivar KJELBERG, Please can you help me?
Thank you so much.
Regards,
Sina
Hi, I want to do a 3D modelling of moving a particle by acoustic wave, throughout a microchannel. I could model by using Comsol 3.5a when the "solve" is stationary, but when I try to solve in transient mode, I got a warning as "inverted mesh element near coordinates". The coordinates are exactly placed in my particle location!! So, I think, this means that there is a problem in meshing process of my particle (because it is so tiny: around 2um in length, width, and heigth). However; the size of my mesh is so tiny (around 1/6 of the wavelength 40um). I read the Comsol modeling guide for many times! But, I couldn't find what's wrong during my modelling? Mr. Ivar KJELBERG, Please can you help me? Thank you so much. Regards, Sina

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Posted: 10 years ago Nov 12, 2014, 1:35 a.m. EST
Hi,

I am trying to model a fluid damper, which involves magnetic field, laminar flow and moving mesh. When I disable laminar flow, and run magnetic field and ale in time dependent(0 to 1s), everything works well. The piston's movement is achieved through ale(prescribed mesh displacement) at a value of A*sin(2*pi*f*t), other boundaries deformed accordingly(as I have unchecked "prescribed z displacement" box). However, when I assign moving wall and sliding wall to the boundaries (similar to the one modelled in Comsol's fluid damper tutorial- i.e moving wall for horizontal, and sliding wall are vertical), I get "last time step is not converged" error and warnings on inverted mesh. I have tried changing the BCs, mesh distribution but none seems to work. I am not sure how to succesfully model this.

Thanks
Hi, I am trying to model a fluid damper, which involves magnetic field, laminar flow and moving mesh. When I disable laminar flow, and run magnetic field and ale in time dependent(0 to 1s), everything works well. The piston's movement is achieved through ale(prescribed mesh displacement) at a value of A*sin(2*pi*f*t), other boundaries deformed accordingly(as I have unchecked "prescribed z displacement" box). However, when I assign moving wall and sliding wall to the boundaries (similar to the one modelled in Comsol's fluid damper tutorial- i.e moving wall for horizontal, and sliding wall are vertical), I get "last time step is not converged" error and warnings on inverted mesh. I have tried changing the BCs, mesh distribution but none seems to work. I am not sure how to succesfully model this. Thanks

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