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How to make COMSOL spread out mesh nodes more evenly?
Posted Apr 18, 2013, 9:27 a.m. EDT 3 Replies
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Hi there,
I'm using a COMSOL model (see attached mph-file) via LiveLink in MATLAB where I especially need to reconstruct certain values throughout the whole domain (in the context of tomography/geophysics). My 3D-domain is split into two parts: one block modelling ground and one block modelling air.
Now, the problem is that COMSOL seems to generate the (free tetrahedral) mesh such that there are certain horizontally oriented layers that are "densely populated" with mesh nodes whereas other layers contain far less mesh nodes (see attached MATLAB figure). This is bad for my reconstruction where I need nodes throughout the whole domain.
Can anybody tell me how I can make COMSOL spread out the mesh nodes more evenly throughout the whole domain?
I've already played with "maximum element size" in COMSOL's mesh configuration. However, in order to get nodes into the less densely populated layers, I have to make the mesh size so small that the overall number of nodes explodes. This is not satisfactory.
Also, if I want to avoid using a "Swept mesh", because for my MATLAB reconstruction algorithm a tetrahedral mesh is better suited.
I'm grateful for any hint into the right direction.
Thanks a lot in advance,
Joerg
I'm using a COMSOL model (see attached mph-file) via LiveLink in MATLAB where I especially need to reconstruct certain values throughout the whole domain (in the context of tomography/geophysics). My 3D-domain is split into two parts: one block modelling ground and one block modelling air.
Now, the problem is that COMSOL seems to generate the (free tetrahedral) mesh such that there are certain horizontally oriented layers that are "densely populated" with mesh nodes whereas other layers contain far less mesh nodes (see attached MATLAB figure). This is bad for my reconstruction where I need nodes throughout the whole domain.
Can anybody tell me how I can make COMSOL spread out the mesh nodes more evenly throughout the whole domain?
I've already played with "maximum element size" in COMSOL's mesh configuration. However, in order to get nodes into the less densely populated layers, I have to make the mesh size so small that the overall number of nodes explodes. This is not satisfactory.
Also, if I want to avoid using a "Swept mesh", because for my MATLAB reconstruction algorithm a tetrahedral mesh is better suited.
I'm grateful for any hint into the right direction.
Thanks a lot in advance,
Joerg
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3 Replies Last Post Apr 18, 2013, 1:58 p.m. EDT
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Posted:
1 decade ago
Hi
you could try to select the edges and start with a seed mesh there with some fixed step size
--
Good luck
Ivar
you could try to select the edges and start with a seed mesh there with some fixed step size
--
Good luck
Ivar
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Posted:
1 decade ago
Hi Ivar,
thanks for your quick answer. What exactly do you mean by "seed"? Is that a technical term from COMSOL or do you just mean that I generate a seperate mesh node for the edges/faces of my domain?
Greetings,
Jörg
thanks for your quick answer. What exactly do you mean by "seed"? Is that a technical term from COMSOL or do you just mean that I generate a seperate mesh node for the edges/faces of my domain?
Greetings,
Jörg
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Posted:
1 decade ago
Hi
My expressio nof "seed" is when you start to mesh parts of a model, i.e. edges of a 2D/3D, this gives node points that the mesher will use to generte the boundary and domain mesh afterwards. You can sometimes, in this way, easily force the meser to respect certain criteria for max or min mesh size without to much effort.
You have also all the custom settings, you can add several "size nodes, as well as dimensions, and the latter allows you to define geoemtrical functions for the node density distribution too
Another term I use are "hard mesh points", this is typically when you add internal boundaries, or just "points on domains or boundaries, to get a node to stick there, and to have easier pickup points/edges for the postprocessing. These geoemtries are not really used for the model or the physics, its just easi hep for pick and select. In the latest COMSOlrelease several of these new features were added to the mesh nodes. I'm not sure everyone has noticed them (2 sub levels down in the tree) but these are really nice and handy for manual tweaking a complex mesh
--
Good luck
Ivar
My expressio nof "seed" is when you start to mesh parts of a model, i.e. edges of a 2D/3D, this gives node points that the mesher will use to generte the boundary and domain mesh afterwards. You can sometimes, in this way, easily force the meser to respect certain criteria for max or min mesh size without to much effort.
You have also all the custom settings, you can add several "size nodes, as well as dimensions, and the latter allows you to define geoemtrical functions for the node density distribution too
Another term I use are "hard mesh points", this is typically when you add internal boundaries, or just "points on domains or boundaries, to get a node to stick there, and to have easier pickup points/edges for the postprocessing. These geoemtries are not really used for the model or the physics, its just easi hep for pick and select. In the latest COMSOlrelease several of these new features were added to the mesh nodes. I'm not sure everyone has noticed them (2 sub levels down in the tree) but these are really nice and handy for manual tweaking a complex mesh
--
Good luck
Ivar