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

[ICEM] Mirror Mesh | Delete duplicate mesh

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 18, 2013, 09:13
Default Mirror Mesh | Delete duplicate mesh
  #1
Member
 
Join Date: Oct 2012
Posts: 32
Rep Power: 14
pythag0ra5 is on a distinguished road
Dear all,

i want to simulate a set-up like shown below:



Therefore, i decided to mesh just this part of the geometry:



In the next step, i want to mirror this part which will result in a mesh which looks like this:



After this, i want to translate / copy this mesh a couple of times in order to get a mesh like shown above.

I generated a mesh for the very simple part (picture 2). As i want to mirror this mesh, i choose "Edit Mesh | Transform Mesh | Mirror Mesh". I worked with the options "Copy", "Merge Nodes" and "Delete duplicate elements" and i selected the whole mesh via frame-selection.

The green surface in my second picture is called "part_9", i think this names comes from my CAD-system (in this case CATIA). After mirroring the mesh, "part_9" still exists. With the options declared above, i would have been expected that this part of the mesh vanishes.

I have the same problems if i translate the mirrored mesh later on, which means that i have some kind of internal walls inside my mesh.

Please tell me where my mistake in thinking is.

Thanks in advance!


pythag0ra5 is offline   Reply With Quote

Old   November 18, 2013, 09:42
Default
  #2
kad
Senior Member
 
Join Date: Feb 2013
Location: Germany
Posts: 200
Rep Power: 24
kad will become famous soon enoughkad will become famous soon enough
ICEM manual says:
"The deleting of elements during the automatic fix will remove one of the two duplicate ele-
ments, thus eliminating this error without creating a hole in the geometry."

E.g. if duplicate elements occur in surface region, deleting both would create a hole in the surface mesh. In your case the volume mesh is all in the same part. So you should be able to just delete those "interface" elementes without getting an error warning.

Furthermore I would not work with the frame selection when dealing with volume mesh. Displaying the whole mesh can easily crash ICEM on weaker computers. I prefer "select items in part" from the selection toolbar.
kad is offline   Reply With Quote

Old   November 18, 2013, 10:12
Default
  #3
Member
 
Join Date: Oct 2012
Posts: 32
Rep Power: 14
pythag0ra5 is on a distinguished road
Sorry, maybe i don't understand the Help-Manual. Does this mean that i do not have to care about those "duplicate" elements or do i have to delete them manually after mirroring the mesh? How can those duplicate elements be deleted?

Thank you very much for your advice concerning the box-selection!
pythag0ra5 is offline   Reply With Quote

Old   November 18, 2013, 10:54
Default
  #4
kad
Senior Member
 
Join Date: Feb 2013
Location: Germany
Posts: 200
Rep Power: 24
kad will become famous soon enoughkad will become famous soon enough
I think you use the term duplicate element wrong. A duplicate element is a cell face that shares all of its node with its neighbor face. So you have two cell faces that have exactly the same nodes and this is a mesh error. It is obvious that these kind of elements are created in the mirror plane. By fixing duplicate elements one of the two duplicate faces is deleted, the other one remains. Duplicate elements are not just "those elements in the mirror plane". There are two things you can do:

1) Define the mirror plane elements as internal walls in your solver.
2) Delete all shell elements in the mirror plane.

If you have to care for them, depends on your case. Mind that the mirror plane could also be a physical wall in other cases like yours. But in your case I would delete the elements because if think it's the easiest way.
kad is offline   Reply With Quote

Old   November 18, 2013, 11:12
Default
  #5
Member
 
Join Date: Oct 2012
Posts: 32
Rep Power: 14
pythag0ra5 is on a distinguished road
Thank you for your fast reply! Maybe another option would be to exclude the shell elements in the mirror-plane from being mirrored?

Nevertheless i want to implement your suggestions, can you please explain me how to delete those shell-elements in the mirror-plane?
pythag0ra5 is offline   Reply With Quote

Old   November 18, 2013, 11:54
Default
  #6
kad
Senior Member
 
Join Date: Feb 2013
Location: Germany
Posts: 200
Rep Power: 24
kad will become famous soon enoughkad will become famous soon enough
Right, that is another option. In your simple case this should be no problem. Nevertheless I always copy the mirror plane elements too, to avoid any uncovered faces or else.

There lots of different and simple ways of deleting the elements. The easiest would to turn on shells and only part_9 in Display tree and select visible. Btw. really great selection modes in ICEM are the floodfill selection up to an specified angle and the select elements inside closed curve loop. They make picking elements from screen very easy. So this would be another way. I guess you are so familiar with ICEM to find the delete elements function?
kad is offline   Reply With Quote

Old   November 19, 2013, 08:35
Default
  #7
Member
 
Join Date: Oct 2012
Posts: 32
Rep Power: 14
pythag0ra5 is on a distinguished road
Hi kad, thank you very much fo your reply! Thanks to your help, i finally got my desired mesh!
pythag0ra5 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
[ICEM] Negative volume error in hybrid mesh siw ANSYS Meshing & Geometry 4 September 3, 2014 06:25
[ICEM] Generating Mesh for STL Car in Windtunnel Simulation tommymoose ANSYS Meshing & Geometry 48 April 15, 2013 05:24
[Gmsh] 2D Mesh Generation Tutorial for GMSH aeroslacker OpenFOAM Meshing & Mesh Conversion 12 January 19, 2012 04:52
[snappyHexMesh] snappyHexMesh won't work - zeros everywhere! sc298 OpenFOAM Meshing & Mesh Conversion 2 March 27, 2011 22:11
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55


All times are GMT -4. The time now is 03:34.