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Meshing Errors In Small Solenoid Simulation
Posted Aug 22, 2012, 5:25 p.m. EDT Mesh Version 4.2 2 Replies
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I am having trouble meshing a somewhat simple solenoid in COMSOL, more specifically, solenoids with a small pitch. I have attached a simple solenoid simulation (created in 4.2) which demonstrates the problem I am having. In this file I am trying to calculate/visualize the flux generation of different solenoid models with a specified current input.
When the pitch of the solenoid is small then I COMSOL will give me a mesh warning or error when generating the free tetrahedral mesh around the solenoid. If you look at the model, you can see COMSOL is having trouble generating the mesh at the input/output of the solenoid. COMSOL has no problem creating a mesh when the pitch and minor radius are increased.
I was able to create a swept mesh based on a free triangular pattern but I found I was unable to create a free tetrahedral mesh around the model (for the 'air' box representing the boundary conditions).
Does anyone know why I might be getting these meshing errors and any suggestions as to what I could try next?
When the pitch of the solenoid is small then I COMSOL will give me a mesh warning or error when generating the free tetrahedral mesh around the solenoid. If you look at the model, you can see COMSOL is having trouble generating the mesh at the input/output of the solenoid. COMSOL has no problem creating a mesh when the pitch and minor radius are increased.
I was able to create a swept mesh based on a free triangular pattern but I found I was unable to create a free tetrahedral mesh around the model (for the 'air' box representing the boundary conditions).
Does anyone know why I might be getting these meshing errors and any suggestions as to what I could try next?
Attachments:
2 Replies Last Post Aug 24, 2012, 6:18 p.m. EDT
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Posted:
1 decade ago
Hi,
The geometry contains a number of short edges, for example, edge 41. The free tetrahedral mesher gives a warning for this edge for the "Normal" mesh size because the length of the edge (0.059 mm) is significantly smaller than the value of the "Minimum element size parameter" given by the Size node (0.9 mm).
You can avoid the creation of the short edges by clearing the "Twist compensation" check box in the Helix 2 node's settings window (under Advanced Settings). Then the resulting geometry meshes without warnings.
Note that it is also possible to first create a swept prism mesh on the solenoid, convert it to a tetrahedral mesh (which is necessary to make it compatible with the surrounding tetrahedral mesh), and then create a tetrahedral mesh for the remaining domains.
The attached model, built using COMSOL 4.3 Update 1, contains two Mesh nodes, one for each meshing approach described above. The model has been saved without meshes to reduce the file size; click Build All for the Mesh 1 and Mesh 2 nodes to create a free mesh or a mesh where the solenoid part uses a swept prism mesh.
Best regards,
Magnus Ringh, COMSOL
The geometry contains a number of short edges, for example, edge 41. The free tetrahedral mesher gives a warning for this edge for the "Normal" mesh size because the length of the edge (0.059 mm) is significantly smaller than the value of the "Minimum element size parameter" given by the Size node (0.9 mm).
You can avoid the creation of the short edges by clearing the "Twist compensation" check box in the Helix 2 node's settings window (under Advanced Settings). Then the resulting geometry meshes without warnings.
Note that it is also possible to first create a swept prism mesh on the solenoid, convert it to a tetrahedral mesh (which is necessary to make it compatible with the surrounding tetrahedral mesh), and then create a tetrahedral mesh for the remaining domains.
The attached model, built using COMSOL 4.3 Update 1, contains two Mesh nodes, one for each meshing approach described above. The model has been saved without meshes to reduce the file size; click Build All for the Mesh 1 and Mesh 2 nodes to create a free mesh or a mesh where the solenoid part uses a swept prism mesh.
Best regards,
Magnus Ringh, COMSOL
Attachments:
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi,
The geometry contains a number of short edges, for example, edge 41. The free tetrahedral mesher gives a warning for this edge for the "Normal" mesh size because the length of the edge (0.059 mm) is significantly smaller than the value of the "Minimum element size parameter" given by the Size node (0.9 mm).
You can avoid the creation of the short edges by clearing the "Twist compensation" check box in the Helix 2 node's settings window (under Advanced Settings). Then the resulting geometry meshes without warnings.
Note that it is also possible to first create a swept prism mesh on the solenoid, convert it to a tetrahedral mesh (which is necessary to make it compatible with the surrounding tetrahedral mesh), and then create a tetrahedral mesh for the remaining domains.
The attached model, built using COMSOL 4.3 Update 1, contains two Mesh nodes, one for each meshing approach described above. The model has been saved without meshes to reduce the file size; click Build All for the Mesh 1 and Mesh 2 nodes to create a free mesh or a mesh where the solenoid part uses a swept prism mesh.
Best regards,
Magnus Ringh, COMSOL
Thank you for your response. It looks disabling the 'twist compensation' fixed the meshing problems. I cannot believe it was something that simple. Thanks again.