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

[ICEM] Problems with meshing a 3D wing w/winglet

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 17, 2013, 17:13
Default Problems with meshing a 3D wing w/winglet
  #1
Member
 
Cesar
Join Date: Nov 2012
Location: Guanajuato, México
Posts: 78
Rep Power: 16
cesarcg is on a distinguished road
Send a message via Skype™ to cesarcg
Hi all,

I'm having problems meshing a 3D wing with a winglet using hexa-mesh. I finished the blocking and ran a quality check for premesh based in determinant and angle criteria and obtained above 0.4 and 19º, respectively. Then I proceeded to convert the premesh to an unstructured mesh.

After the mesh was generated, I ran a quality check for all the cells based in determinant, min angle, and orthogonal quality and obtained above 0.4, 19º, and 0.35, respectively. The problem here is that Icem is printing a message about 5028 cells with undefined quality during each check. I also did a check for problems finding out that there are 10 penetrating cells that can be fixed without improving the issue about the undefined quality cells. Geometry and blocking files are below:

https://www.dropbox.com/s/hw85r1x1n8...luidDomain.tin
https://www.dropbox.com/s/uffxplfl5x...013_Coarse.blk

Does anybody know how to locate these undefined quality cells in order to fix them? I need to solve this since the mesh is giving me problems in Fluent because they are detected as cells of low orthogonal quality (below 0.01) and I blame these ones to the instability and difficulty to convergence of numerical solution. I hope someone can help me out with this since it is part of my dissertation and I'm running out of time.

Thanks in advance,
César
cesarcg is offline   Reply With Quote

Old   March 17, 2013, 17:54
Default
  #2
Member
 
Alexander
Join Date: Nov 2009
Location: Blansko, Czech Republic
Posts: 30
Rep Power: 17
Pospelov is on a distinguished road
Hello, Cesarcg!
You blocks is very good!
You should try check your grid by determinate 3x3x3 in rang -1 to 1. I think you will see your error there.
Pospelov Alexander
Pospelov is offline   Reply With Quote

Old   March 17, 2013, 18:20
Default
  #3
Member
 
Cesar
Join Date: Nov 2012
Location: Guanajuato, México
Posts: 78
Rep Power: 16
cesarcg is on a distinguished road
Send a message via Skype™ to cesarcg
Quote:
Originally Posted by Pospelov View Post
Hello, Cesarcg!
You blocks is very good!
You should try check your grid by determinate 3x3x3 in rang -1 to 1. I think you will see your error there.
Pospelov Alexander
Hi Alexander,

Thanks for your suggestion but I already did that and didn't find the error. I ran out of ideas to look for the problem.

Regards,
César
cesarcg is offline   Reply With Quote

Old   March 17, 2013, 19:32
Default
  #4
Member
 
Alexander
Join Date: Nov 2009
Location: Blansko, Czech Republic
Posts: 30
Rep Power: 17
Pospelov is on a distinguished road
If you delete part solid, you would not have any problem in ICEM. I've done all checks in ANSYS 13.0.
But it's takes me some time, because I've got not good computer at home. )
Pospelov Alexander
Pospelov is offline   Reply With Quote

Old   March 18, 2013, 03:12
Default
  #5
Far
Senior Member
 
Sijal
Join Date: Mar 2009
Location: Islamabad
Posts: 4,558
Blog Entries: 6
Rep Power: 54
Far has a spectacular aura aboutFar has a spectacular aura about
Send a message via Skype™ to Far
Excellent. Outclass.
Far is offline   Reply With Quote

Old   March 18, 2013, 10:55
Default
  #6
Super Moderator
 
diamondx's Avatar
 
Ghazlani M. Ali
Join Date: May 2011
Location: Tokyo, Japan
Posts: 1,385
Blog Entries: 23
Rep Power: 29
diamondx will become famous soon enough
Still i think tetra+prism is more suitable for this. multizone will be the best. a premesh info inform me that you have generated 9 000 000 nodes. you really need some strong hardware there to simulate this...
__________________
Regards,
New to ICEM CFD, try this document --> https://goo.gl/KAOIwm
Ali
diamondx is offline   Reply With Quote

Old   March 18, 2013, 11:00
Default
  #7
Far
Senior Member
 
Sijal
Join Date: Mar 2009
Location: Islamabad
Posts: 4,558
Blog Entries: 6
Rep Power: 54
Far has a spectacular aura aboutFar has a spectacular aura about
Send a message via Skype™ to Far
@Ali. No of nodes can be reduced as I can see many refinements in unimportant areas. And I like the blocking strategy...
Far is offline   Reply With Quote

Old   March 18, 2013, 11:04
Default
  #8
Super Moderator
 
diamondx's Avatar
 
Ghazlani M. Ali
Join Date: May 2011
Location: Tokyo, Japan
Posts: 1,385
Blog Entries: 23
Rep Power: 29
diamondx will become famous soon enough
the blocking is perfect of course
__________________
Regards,
New to ICEM CFD, try this document --> https://goo.gl/KAOIwm
Ali
diamondx is offline   Reply With Quote

Old   March 18, 2013, 11:25
Default
  #9
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
One possible solution could be to deactivate line_2 elements while running quality checks. Quality is of course not defined for line elements.
kad is offline   Reply With Quote

Old   March 18, 2013, 12:42
Default
  #10
Member
 
Cesar
Join Date: Nov 2012
Location: Guanajuato, México
Posts: 78
Rep Power: 16
cesarcg is on a distinguished road
Send a message via Skype™ to cesarcg
Quote:
Originally Posted by Pospelov View Post
If you delete part solid, you would not have any problem in ICEM. I've done all checks in ANSYS 13.0.
But it's takes me some time, because I've got not good computer at home. )
Pospelov Alexander
Hi Alexander,
Thanks for your suggestions. I followed what you've recommended but I just figured out that my problem may not be because the part solid present during unstructured mesh generation neither the translator to mesh for fluent. I ran the mesh quality check before and after export the mesh to fluent and ICEM and got the same minimum values for the different criteria (min angle=21.4º, min determinant=0.35, and min orthogonal quality=0.24). So I guess there is no problem with ICEM.
I think this values are good enough to run the simulation with no big problems, but when read the mesh in fluent, it prints that the orthogonal quality mesh is low (7.35845e-3). I think that I should make a check with gambit and see what it tells.

Quote:
@Ali. No of nodes can be reduced as I can see many refinements in unimportant areas. And I like the blocking strategy...
Hi Far,
Hope that you are doing great. Can you tell me where the number of nodes can be reduced according to your experience? I know that there are some regions that can be improved and your advices would be very helpful.

Quote:
One possible solution could be to deactivate line_2 elements while running quality checks. Quality is of course not defined for line elements.
Hi Kad,
I did what you suggested and you are right. I didn't know that. Thanks a lot.

---------------------
Thanks to everyone,
César
cesarcg is offline   Reply With Quote

Old   March 18, 2013, 13:12
Default
  #11
Far
Senior Member
 
Sijal
Join Date: Mar 2009
Location: Islamabad
Posts: 4,558
Blog Entries: 6
Rep Power: 54
Far has a spectacular aura aboutFar has a spectacular aura about
Send a message via Skype™ to Far
Quote:
Thanks for your suggestions. I followed what you've recommended but I just figured out that my problem may not be because the part solid present during unstructured mesh generation neither the translator to mesh for fluent. I ran the mesh quality check before and after export the mesh to fluent and ICEM and got the same minimum values for the different criteria (min angle=21.4º, min determinant=0.35, and min orthogonal quality=0.24). So I guess there is no problem with ICEM.
I think this values are good enough to run the simulation with no big problems, but when read the mesh in fluent, it prints that the orthogonal quality mesh is low (7.35845e-3). I think that I should make a check with gambit and see what it tells.
Check other parameters like volume change, dihedral angle. And identify areas in Fluent by looking at contour plot of orthogonal quality and improve that area in ICEM.



Quote:
Hi Far,
Hope that you are doing great. Can you tell me where the number of nodes can be reduced according to your experience? I know that there are some regions that can be improved and your advices would be very helpful.
Spanwise mesh is not important as compared to normal to surface mesh is. Inlet and outlet areas in far-field are less important, reduce mesh there.
Far is offline   Reply With Quote

Reply

Tags
hexa meshing, orthogonal quality, winglets, wings

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
meshing for flapping wing simulation sultan FLUENT 5 February 17, 2013 09:31
3D wing + wind tunnel hexa structured meshing icemaniac178 ANSYS Meshing & Geometry 9 October 28, 2010 10:37
Meshing for 3D wing with tubercle on the leading edge in GAMBIT nvtrieu FLUENT 0 August 14, 2010 11:13
Meshing problems using Gambit Vianney FLUENT 4 May 30, 2009 04:45
meshing F1 front wing Steve FLUENT 0 April 17, 2003 13:37


All times are GMT -4. The time now is 06:59.