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Using distributed mesh in 3D
Posted 13 juil. 2011, 12:06 UTC−4 Mesh Version 4.2 1 Reply
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I'm trying to model turbulent flow through a section of cylindrical pipe using a 3D model (I know it is far more efficient in 2D-axisymmetric, but this is just a starting sim that will be expanded later and require 3D). I'd like to assign the mesh across the circular cross-section so that I get a high density of nodes near the circumference of the pipe and a lower density near the center, and then just sweep the mesh along the length of the pipe. Problem is that I can't figure out how to distribute the mesh properly across the circular face. I tried using a mapped mesh for that face and then assigning a distribution, but it seems I can only assign the distribution to the edges, and the result yields extremely poor quality elements.
I'm guessing that I'm missing something obvious. Can anyone offer some advice?
Thanks,
Chris
I'm guessing that I'm missing something obvious. Can anyone offer some advice?
Thanks,
Chris
1 Reply Last Post 14 juil. 2011, 16:26 UTC−4
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Posted:
1 decade ago
I received a response back from COMSOL and wanted to include it here in case anyone has a similar issue:
The mesh distribution you describe can be best achieved on a cylindrical geometry by following these steps:
1) Right-click Mesh 1 and select Delete Sequence to clear the mesh of any previous features.
2) Right-click Mesh 1 and select More Operations > Free Triangular. Left- and then right-click on one circular face of the cylinder to add it to the Selection list.
3) Right-click Free Triangular 1 and add a Size feature.
4) In the Settings window for Size under the heading Element Size select Custom.
5) Under the Element Size Parameters heading, check the boxes beside Maximum element size, Minimum element size, Maximum element growth rate, and Resolution of curvature. Modify these fields to suit your model and preferred mesh distribution. Specific information about these Element Size Parameters is located in the COMSOL Multiphysics User's Guide on pp. 619-620. Note that the Resolution of Curvature field controls how fine your mesh is around the outer circular edge and the Maximum element growth rate determines how quickly this mesh density decreases towards a coarser mesh near the center of the circle.
6) Right-click Mesh 1 and select Swept; the default setting here is for the mesh created on the circular face to be swept through the pipe.
7) Right-click Mesh 1 and select Boundary Layers. Click on Boundary Layer Properties. Add all four non-circular boundaries to the Selection list and specify the Boundary layer Properties as needed (more information on these properties can be found in the COMSOL Multiphysics Reference Guide on pp.
109-110).
8) Click the Build All icon in the Settings window.
Note that step 7 was included, because for modeling turbulent flow a boundary layer mesh along any boundaries parallel to the fluid flow is recommended.
The mesh distribution you describe can be best achieved on a cylindrical geometry by following these steps:
1) Right-click Mesh 1 and select Delete Sequence to clear the mesh of any previous features.
2) Right-click Mesh 1 and select More Operations > Free Triangular. Left- and then right-click on one circular face of the cylinder to add it to the Selection list.
3) Right-click Free Triangular 1 and add a Size feature.
4) In the Settings window for Size under the heading Element Size select Custom.
5) Under the Element Size Parameters heading, check the boxes beside Maximum element size, Minimum element size, Maximum element growth rate, and Resolution of curvature. Modify these fields to suit your model and preferred mesh distribution. Specific information about these Element Size Parameters is located in the COMSOL Multiphysics User's Guide on pp. 619-620. Note that the Resolution of Curvature field controls how fine your mesh is around the outer circular edge and the Maximum element growth rate determines how quickly this mesh density decreases towards a coarser mesh near the center of the circle.
6) Right-click Mesh 1 and select Swept; the default setting here is for the mesh created on the circular face to be swept through the pipe.
7) Right-click Mesh 1 and select Boundary Layers. Click on Boundary Layer Properties. Add all four non-circular boundaries to the Selection list and specify the Boundary layer Properties as needed (more information on these properties can be found in the COMSOL Multiphysics Reference Guide on pp.
109-110).
8) Click the Build All icon in the Settings window.
Note that step 7 was included, because for modeling turbulent flow a boundary layer mesh along any boundaries parallel to the fluid flow is recommended.