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

[ICEM] mesh cylinder

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

Like Tree2Likes
  • 1 Post By PSYMN
  • 1 Post By Far

Reply
 
LinkBack Thread Tools Display Modes
Old   March 2, 2012, 12:04
Default mesh cylinder
  #1
New Member
 
Join Date: Oct 2011
Posts: 14
Rep Power: 5
cfddwarf is on a distinguished road
Hey guys,
Iam still having problems with my geometry... Could someone please have a look at it and help me out? Seriously I have been struggling with this for a week now.
The Premesh Quality shows that the elements are not really regularly in my cylinder.
Ive tried meshing a single cylinder with a single surface, opensided. the same problem occurs. If i put a surface on the side where its not supposed to be, it works perfectly.
could someone please help me and tell me where the problem lies? I bet its all about the associations again, but i cant figure it out
Iam attaching the geometry and bulk files.
Attached Images
File Type: png Screenshot.png (62.2 KB, 81 views)
Attached Files
File Type: gz vortexmixer.blk.tar.gz (11.5 KB, 13 views)
File Type: gz vortexmixer.tin.tar.gz (9.7 KB, 13 views)
cfddwarf is offline   Reply With Quote

Old   March 5, 2012, 07:01
Default
  #2
Senior Member
 
Christoph
Join Date: May 2011
Location: Germany
Posts: 182
Rep Power: 9
energy382 is on a distinguished road
Hey dude,

at first sight, i actually thought the problems were related to the associations. But take a look at your blocking! None of the blocks were connected. So I had to merge verticies, delete and recreate the o-grid (you have to do the split up to the bottom!).

Det 3x3x3/Quality now > 0,6

you have to set edge parameters yet.
Attached Files
File Type: zip online.zip (22.9 KB, 9 views)
energy382 is offline   Reply With Quote

Old   March 5, 2012, 08:40
Default
  #3
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,954
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
Quote:
None of the blocks were connected.
so created through bottom-up approach!!!!!
Far is offline   Reply With Quote

Old   March 5, 2012, 09:31
Default
  #4
Senior Member
 
Christoph
Join Date: May 2011
Location: Germany
Posts: 182
Rep Power: 9
energy382 is on a distinguished road
Quote:
Originally Posted by Far View Post
so created through bottom-up approach!!!!!
bottom-up or top-down.....what's the point?

blocking was just incorrect. Or is it a a appeal for the use of top-down approach!?
energy382 is offline   Reply With Quote

Old   March 5, 2012, 12:10
Default
  #5
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,954
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
Quote:
Originally Posted by energy382 View Post
bottom-up or top-down.....what's the point?

blocking was just incorrect. Or is it a a appeal for the use of top-down approach!?
Both.

For this geometry one has to use both approaches to build the topology. While working on the bottom-up approach, the blocking vertices may be disconnected. So it is better to keep in mind this issue.
Far is offline   Reply With Quote

Old   March 5, 2012, 12:15
Default
  #6
Senior Member
 
Christoph
Join Date: May 2011
Location: Germany
Posts: 182
Rep Power: 9
energy382 is on a distinguished road
ok, i get your point now
energy382 is offline   Reply With Quote

Old   March 5, 2012, 13:05
Default
  #7
Super Moderator
 
diamondx's Avatar
 
Ghazlani M. Ali
Join Date: May 2011
Location: Canada
Posts: 1,291
Blog Entries: 23
Rep Power: 20
diamondx will become famous soon enough
Hello everyone,
sorry for hijacking this post. I tried to mesh the geometry and i realize that it does same thing, so where i did is adding surfaces in blue as you can see in pictures below(first one), everytime i close with a surface, the mesh is good, if i dont close like the last picture, the mesh come out bad. my associations are goood since i tried it on that little inlet there. where does the problem comes from.
Attached Images
File Type: jpg issue 1.jpg (99.3 KB, 39 views)
File Type: jpg issue 2.jpg (102.6 KB, 30 views)
File Type: jpg issue 3.jpg (99.7 KB, 34 views)
__________________
Regards,
New to ICEM CFD, try this document --> http://goo.gl/G2gkE
Ali
diamondx is offline   Reply With Quote

Old   March 5, 2012, 22:47
Default
  #8
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,954
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
Just created one block and fit it into the square box and cylinder. Then split the main block into 9 blocks: 8 for square box and one for cylinder. Created O-block in cylinder up to bottom of square section. Then used bottom-up approach (extrude face along curve) to create the blocking for the rectangular pipes (2 on each side and 8 in total)



Quote:
every time i close with a surface, the mesh is good
I didn't add any surface and still has no problem with meshing.
Attached Files
File Type: zip vortexmixer_Far.zip (18.7 KB, 13 views)
Far is offline   Reply With Quote

Old   March 5, 2012, 23:13
Default
  #9
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,954
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
Applied link edges command: linked the top square edges to bottom square edges

Far is offline   Reply With Quote

Old   March 6, 2012, 05:22
Default
  #10
Senior Member
 
Christoph
Join Date: May 2011
Location: Germany
Posts: 182
Rep Power: 9
energy382 is on a distinguished road
you should resign from your job and start working as a ICEM instructor

Probably you'll earn even more money

I would definitely call on your services
energy382 is offline   Reply With Quote

Old   March 6, 2012, 06:51
Default
  #11
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,954
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
Quote:
you should resign from your job and start working as a ICEM instructor
Done . But how did you know this
Far is offline   Reply With Quote

Old   March 6, 2012, 13:53
Default
  #12
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,954
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
made edge settings and quality is also further improved >>> 0.84

Attached Files
File Type: zip vortexmixer_Far.zip (25.2 KB, 3 views)

Last edited by Far; March 7, 2012 at 00:53. Reason: image
Far is offline   Reply With Quote

Old   March 6, 2012, 13:56
Default
  #13
Super Moderator
 
diamondx's Avatar
 
Ghazlani M. Ali
Join Date: May 2011
Location: Canada
Posts: 1,291
Blog Entries: 23
Rep Power: 20
diamondx will become famous soon enough
bottom up approach works fine.
like a boss, i agree with energy382. thanks anyway
__________________
Regards,
New to ICEM CFD, try this document --> http://goo.gl/G2gkE
Ali
diamondx is offline   Reply With Quote

Old   March 7, 2012, 10:40
Default
  #14
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,662
Blog Entries: 1
Rep Power: 36
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
While I agree with Far that top down is easiest and fastest way to handle this model...

Bottom up would also work fine. You just made one real mistake...

When you create a block in ICEM CFD, it assumes that all faces must project to the nearest surface. If that block is attached to another block of the same material, then the projection of the face between the blocks is turned off because that is an "internal face". This happens automatically, but you can control it interactively thru the face associations.

In your case, each of the cylinders (geometry) was attached to a larger model on one end, so there was no surface there. However, you had not actually connected your blocks (by merging the verts at the corners...). So each block thought that it was free standing and needed to form a closed surface. However, without a surface to project the inner end to, the elements simply projected to wrong surface...

Energy382 solved the problem when he merged the verts (and the blocking), because as soon as the faces were merged it automatically changed the projection on those faces to "none".
DungPham likes this.
__________________
-----------------------------------------
Please help guide development at ANSYS by filling in these surveys

Public ANSYS ICEM CFD Users Survey

This second one is more general (Gambit, TGrid and ANSYS Meshing users welcome)...

CFD Online Users Survey
PSYMN is offline   Reply With Quote

Old   March 7, 2012, 11:22
Default
  #15
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,954
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
Quote:
Originally Posted by Far
Just created one block and fit it into the square box and cylinder. Then split the main block into 9 blocks: 8 for square box and one for cylinder. Created O-block in cylinder up to bottom of square section. Then used bottom-up approach (extrude face along curve) to create the blocking for the rectangular pipes (2 on each side and 8 in total.
I used both, first top-down for main geometry and bottom-up for 8 pipes, therefore I didn't come across issue like unconnected blocks. Hence no need to merge vertices.
PSYMN is this good strategy?


Quote:
Originally Posted by energy382 View Post
you should resign from your job and start working as a ICEM instructor
Probably you'll earn even more money
@ PSYMN : are my skills good enough (though I don't think so) to fit into this role? Any chance at ANSYS?
DungPham likes this.
Far is offline   Reply With Quote

Old   February 17, 2013, 00:03
Default O-grid faces selection
  #16
New Member
 
MOISE DION
Join Date: Sep 2011
Posts: 8
Rep Power: 5
moisedion is on a distinguished road
I was wondering about the criteria in selection an O-grid faces?
What to account for when choosing the faces after dividing a given block with an o-grid method in ICEM.
Thanks for your answers
moisedion is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
No layers in a small gap bobburnquist OpenFOAM Native Meshers: snappyHexMesh and Others 6 August 26, 2015 09:38
[ICEM] Injector Tube into a Big Cylinder - How to mesh? Leepox ANSYS Meshing & Geometry 2 November 25, 2011 11:45
rotating cylinder using sliding mesh Tim Daly FLUENT 1 November 10, 2008 00:02
ICEM block mesh with a ball in a cylinder tube Li CFX 6 August 11, 2008 05:44
mesh problem for cylinder akr FLUENT 1 January 30, 2007 00:43


All times are GMT -4. The time now is 09:11.