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

Differents Meshes for an unique surface

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 1, 2009, 11:50
Default Differents Meshes for an unique surface
  #1
New Member
 
Tatiane H.
Join Date: Nov 2009
Posts: 4
Rep Power: 16
Tati is on a distinguished road
Hi, everyone!

I'm simulating an air duct in CFX. At first, the air pass through a rectangular geometry and after, the air goes down through a cylindrical geometry.
I appreciate if someone could help me to do after putting " All Quad" in the rectangular part and another kind of mesh at the cylindrical part (for this, I put surface mesh and after, I extruded the surfaces).
When I set the problem, the solver didn't run because there were 4 isolated surfaces. I believe the problem is in the meshes that coincide in a same surface.
What can I do?!

Thanks for any response!
Tati is offline   Reply With Quote

Old   December 1, 2009, 15:46
Default
  #2
Member
 
Pratik Mehta
Join Date: Mar 2009
Posts: 32
Rep Power: 17
pratikmehta is on a distinguished road
hi ,
Your method is correct before I comment, can you please tell me what meshing tool you have ?.


thanks


best regards
Pratik
pratikmehta is offline   Reply With Quote

Old   December 2, 2009, 05:53
Default
  #3
New Member
 
Tatiane H.
Join Date: Nov 2009
Posts: 4
Rep Power: 16
Tati is on a distinguished road
Hi, Pratik!

I'm really grateful for you help.
For surface mesh I have All tri, Quad Dominant, Qua w/one tri and All Quad. For volume mesh, there are Tetra/Mixed, Hexa Dominant and Cartesian.
I actually don't know too what kind of mesh to put on the cylindrical part.

Thanks a lot!

Tatiane
Tati is offline   Reply With Quote

Old   December 2, 2009, 07:07
Default
  #4
New Member
 
Ramandeep Singh
Join Date: Nov 2009
Posts: 20
Rep Power: 16
RAMAN6089 is on a distinguished road
i guess u are using a way to many types of mesh.
the problem can be simply solved considering prism on the boundary surface and Hexa or Quad meshing as the volume. please read the tutorials.
__________________
regards,
Raman
RAMAN6089 is offline   Reply With Quote

Old   December 2, 2009, 09:44
Default
  #5
Member
 
Pratik Mehta
Join Date: Mar 2009
Posts: 32
Rep Power: 17
pratikmehta is on a distinguished road
hi,

As mention by Raman that you could just do tet + prism meshing and aviod the issues which you are falling in now . Well I would actually suggest to do the the following way if you prefer doing it differently

For the rectangular geometry ,you can do hybrid mesh ( tet +prism layers ) and later you can just extrude the face to represent circular part. In this case all you need to know the extrussion lenght and the curve for attaching it. So your .tin file will only have surfaces of the rectangular geometry and so the the circular part ( which wil be extruded part ).


best of luck

Ciao
Pratik
pratikmehta is offline   Reply With Quote

Old   December 2, 2009, 11:37
Default
  #6
New Member
 
Join Date: Nov 2009
Posts: 11
Rep Power: 16
champshof is on a distinguished road
check the quality of your mesh with your meshing tool, this will find the isolated surfaces, zoom in on them and post a snapshot of it overhere, this gives us a beter view of your mesh and your problem
champshof is offline   Reply With Quote

Old   December 3, 2009, 12:38
Default
  #7
New Member
 
Tatiane H.
Join Date: Nov 2009
Posts: 4
Rep Power: 16
Tati is on a distinguished road
First of all, thanks a lot for all the helps given!
I tried tetra/prism layer and it simulated well.
Now I'll try the extrude way and see if I have success on it.
I put the figure, but i don't know if it was what you wanted, Champshof, as i'm a really begginer on CFX.

Best regards for everyone!
Attached Images
File Type: jpg air_duct.jpg (98.4 KB, 18 views)
Tati is offline   Reply With Quote

Old   December 4, 2009, 06:04
Default
  #8
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,665
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
It looks like you have not merged the cylinder and square duct into the same solid. This means they will be independent fluid regions (unless you join them with a GGI but only do this when you have no other choice).
ghorrocks is offline   Reply With Quote

Old   December 4, 2009, 06:16
Default
  #9
New Member
 
Join Date: Nov 2009
Posts: 11
Rep Power: 16
champshof is on a distinguished road
As wat ghorrock said, it looks like you have a H-grid mesh for the rectangular geometry and a O-grid mesh for the cylindrical geometry. Try to merge the O-grid mesh into the H-grid mesh, this will probably solve your problem.

A GGI is an option but I wouldn't do that because it look like an important region of your problem and it will cause a big accuracy loss (unless you refine the mesh on you interface several times)
champshof is offline   Reply With Quote

Old   December 8, 2009, 12:36
Default
  #10
New Member
 
Tatiane H.
Join Date: Nov 2009
Posts: 4
Rep Power: 16
Tati is on a distinguished road
Hi, people.

I tried to merge the O-grid but the isolated volumes still exist. I tried Hexa-Dominant too, but the mesh appears all desconfigurated. So, I computed tetra/mixed and it's okay!
But, I'll keep trying doing it in a different way.

Thanks a lot for all helps!

Best regards,

Tatiane.
Tati is offline   Reply With Quote

Reply

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
[Gmsh] Error : Self intersecting surface mesh, computing intersections & Error : Impossible velan OpenFOAM Meshing & Mesh Conversion 3 October 22, 2015 12:05
[Gmsh] Problem with Gmsh nishant_hull OpenFOAM Meshing & Mesh Conversion 23 August 5, 2015 03:09
[Gmsh] boundaries with gmshToFoam‏ ouafa OpenFOAM Meshing & Mesh Conversion 7 May 21, 2010 13:43
CFX4.3 -build analysis form Chie Min CFX 5 July 13, 2001 00:19
Empty surface in sliding meshes. Pierre Ricco FLUENT 2 March 14, 2001 17:01


All times are GMT -4. The time now is 13:20.