CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens > STAR-CCM+

Trimmer & prism layer

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 1, 2009, 18:07
Default Trimmer & prism layer
  #1
New Member
 
Peres
Join Date: Jul 2009
Posts: 22
Rep Power: 17
peresah is on a distinguished road
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
Attached Images
File Type: jpg volume.jpg (97.2 KB, 207 views)
File Type: jpg volume2.jpg (82.6 KB, 207 views)
peresah is offline   Reply With Quote

Old   October 5, 2009, 08:26
Default
  #2
New Member
 
Peres
Join Date: Jul 2009
Posts: 22
Rep Power: 17
peresah is on a distinguished road
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.
peresah is offline   Reply With Quote

Old   October 6, 2009, 06:21
Default
  #3
Senior Member
 
Join Date: Mar 2009
Posts: 260
Rep Power: 18
Maddin is on a distinguished road
Same problem I had some months ago. I could make the mesh nicer with a mesh alignment.
Maddin is offline   Reply With Quote

Old   October 6, 2009, 11:35
Default
  #4
New Member
 
Peres
Join Date: Jul 2009
Posts: 22
Rep Power: 17
peresah is on a distinguished road
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...
peresah is offline   Reply With Quote

Old   October 6, 2009, 12:52
Default
  #5
Senior Member
 
Join Date: Mar 2009
Posts: 260
Rep Power: 18
Maddin is on a distinguished road
Did you made a good feature curve? I had often problems when this curve wasn't fine enough.
Maddin is offline   Reply With Quote

Old   October 6, 2009, 14:32
Default
  #6
New Member
 
Peres
Join Date: Jul 2009
Posts: 22
Rep Power: 17
peresah is on a distinguished road
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.
peresah is offline   Reply With Quote

Old   October 6, 2009, 14:39
Default
  #7
Senior Member
 
Join Date: Mar 2009
Posts: 260
Rep Power: 18
Maddin is on a distinguished road
Use CCM... StarDesign always tells me I shall use auto repair but "my" StarDesign don't has this function.
Maddin is offline   Reply With Quote

Reply

Tags
mesh trimmer prism layer

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
ICEM Prism Layer transition between surface with prism layers and one without TWaung ANSYS Meshing & Geometry 2 October 12, 2009 14:56
Prism Layer in STAR-CCM+ Antimony Siemens 11 July 2, 2009 06:26
Icemcfd: Preventing prism inflation collisions? Joe CFX 1 July 31, 2007 09:13
problem in convergence with the prism layer genera rakesh CFX 3 September 18, 2006 10:13
errors Fahad Main CFD Forum 0 March 23, 2004 13:20


All times are GMT -4. The time now is 07:49.