CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > ANSYS Meshing & Geometry

[ICEM] bad elements on symmetry surface

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 15, 2017, 22:26
Default bad elements on symmetry surface
  #1
New Member
 
Join Date: May 2016
Posts: 20
Rep Power: 10
Pawel Zdunek is on a distinguished road
Hey guys,

what could be the reason of bad elements like the ones on the picture?
All of the bad elements are aligned with edges/borders of blocks, I made sure those blocks faces are associated with correct surface, likewise with edges.

Thanks for any help.
Attached Images
File Type: jpg icembadelements.jpg (159.6 KB, 13 views)
Pawel Zdunek is offline   Reply With Quote

Old   June 16, 2017, 05:18
Default
  #2
Senior Member
 
Sebastian Engel
Join Date: Jun 2011
Location: Germany
Posts: 567
Rep Power: 21
bluebase will become famous soon enough
Hi Pawal,

it's hard to see the area of interest.
Can you make a detail screen shot of the worst elements only?
Modify the range of the quality histogramm to -1 to 1 (instead of 0 to 1) and print only two bars, then show only the elements within -1/0 range.

You can also try 'Scan Plan' in the context menu of Pre-Mesh to inspect the problematic areas further. Here you can draw a complete layer of your mesh and see the area in crosssectional view.

A general thing: sometimes curves(,points) and surfaces do not align proberly. So when you have face to surface association and edge to curve association, then you might have a little bump around your curves. Check whether the curves of interest really are at the surface. Try projecting the curves to the surface again.

With regards,
Sebastian
bluebase is offline   Reply With Quote

Old   June 16, 2017, 20:51
Default
  #3
New Member
 
Join Date: May 2016
Posts: 20
Rep Power: 10
Pawel Zdunek is on a distinguished road
Hi,
thank you very much for taking time to help me

I managed to get rid of bad elements aligned on symmetry plane along the outlets (smaller pipes going vertical) by removing those edges' association with symmetry (purple) surface. That was quite surprising for me, I thought those should be projected on symmetry plane, however projecting(associating) them generated bad elements from picture from 1st post. I also improved quality by working on edges spacing, which was really poor in some places and clearly contributed to bad elements (now it's also poor but alittle bit better).

I am afraid that some (most) of bad elements are due to wrong association of given entities - it looks like two meshes -worst elements and ok elements - are projected simultaneously on a symmetry plane.
Attached Images
File Type: jpg icembadelements2.jpg (125.2 KB, 8 views)
Pawel Zdunek is offline   Reply With Quote

Old   June 16, 2017, 21:05
Default
  #4
New Member
 
Join Date: May 2016
Posts: 20
Rep Power: 10
Pawel Zdunek is on a distinguished road
ok it looks like those were the cause of bad elements:
-redundant association of both faces and edges to given surface and curve (is that a common thing in ICEM, because i'm not sure if it's even a thing?)
-wrong association of given edges to given surfaces - that's a bigger problem, some of my edges converge into vertices associated to the same point - that's my big big mistake. Will work on it and update for the future users.
Pawel Zdunek is offline   Reply With Quote

Reply


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
[snappyHexMesh] Missing elements near surface with snappyHexMesh jmf OpenFOAM Meshing & Mesh Conversion 6 November 10, 2017 15:16
[snappyHexMesh] Problem with Sanpper, surface still Rough Zephiro88 OpenFOAM Meshing & Mesh Conversion 7 November 5, 2014 13:05
Bad surface mesh on detailed car jpesich STAR-CCM+ 1 September 23, 2014 23:33
Possible Bug in pimpleFoam (or createPatch) (or fluent3DMeshToFoam) cfdonline2mohsen OpenFOAM 3 October 21, 2013 10:28
Problems of Duns Codes! Martin J Main CFD Forum 8 August 15, 2003 00:19


All times are GMT -4. The time now is 13:58.