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Old   October 1, 2009, 18:07
Default Trimmer & prism layer
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Peres
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Heya

I've some questions concerning the volume mesh tools - the trimmer and the prism layer.

1) Trimmer: It seems that the trimmer only allows a growth ratio of 1.5 during refinement/coarsening, i.e. the cell size always doubles or halfens during refinement. Has anyone else noticed this? The "Template growth" property doesn't seem to change this behaviour since it appears to to control the number of cells of the same size.

2) Prism layer: I'm having a hard time getting a "nice"/"structured" mesh in the interface between the prism layer and the trimmer (see the attached pictures, a vertical plane is also shown to show the mesh here). The prism layer isn't completely circular like the pile. I have the following boundaries: A top plane (pressure outlet), a bed plane (slip-wall, disabled prism layer) and a pile connecting the two (wall, prism layer). I've tried to choose the value of the prism layer thickness, so it is a "reciprocal" of the base trimmer size... I've also tried aligning the trimmed mesh, using the point that intersects the prism outer layer and the core mesh. Have anyone experienced similar difficulties and perhaps some solutions?

Kindly Peres
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File Type: jpg volume2.jpg (82.6 KB, 123 views)
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Old   October 5, 2009, 08:26
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Just for information, I've had it confirmed from the Star-CCM+ support, that the growth rate of 1.5 for the trimmer cannot be changed, it is the fundamental behaviour of the trimmer.
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Old   October 6, 2009, 06:21
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Same problem I had some months ago. I could make the mesh nicer with a mesh alignment.
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Old   October 6, 2009, 11:35
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Thanks Maddin.

Yeah, I also managed to improve the apparent quality by basing the volume mesh on a remeshed surface of an imported mesh with a higher curvature resolution (100 pts per circle, cannot go higher in Stardesign). There still appears some strange node connections on the vertical plane section which is derived "on the fly", but when I shift the plane section laterally to either side, the mesh looks allright - so I think this is just a artifact...

However, using the trimmer together with the prism layer still gives some strange connections... I think I'm opting for some more advanced mesh generation software...
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Old   October 6, 2009, 12:52
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Did you made a good feature curve? I had often problems when this curve wasn't fine enough.
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Old   October 6, 2009, 14:32
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Thanks for the suggestion. I've had some troubles with Stardesign not responding if I increase the mesh resolution, but I may look into this.
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Old   October 6, 2009, 14:39
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Use CCM... StarDesign always tells me I shall use auto repair but "my" StarDesign don't has this function.
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