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

[ICEM] Closed geometry?

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 21, 2012, 06:35
Default Closed geometry?
  #1
Member
 
Join Date: Dec 2012
Posts: 32
Rep Power: 13
powpow is on a distinguished road
Hallo,

I have a general question regarding a CAD-Model that can be used with ICEM CFD.

I have to do a simple CFD-Simulation how an additional tube in a test chamber influences the air flow.
The air enters the test chamber at Position 1. Then, one part of the air leaves the chamber through the nozzle at positon 2, the rest of the air through the new tube (Position 3).
So I build a CAD-Model of the test chamber with CATIA V5. The CAD-Model is a surface model, no solid.

I'd like to create a mesh with 10 layers of prism around the tube and the small nozzle, the rest of the volume should be filled with tetra.

Before I can do this, I have to create BODIES I think?!

Therefore I need closed surfaces I think!?

So here are my questions:

1. Do I have to add surfarces at the positions 1-3 (green circles)? Doing so would close my test chamber.

2. Do I also have to add surfaces at the positions 4-8 (red circles with green surrounding)?

3. How many BODIES do I have to create?

I couldn't find some information regarding such geometry in the tutorials or the Manual, so I would be very thankful if someone has an idea...

Cheers powpow
Attached Images
File Type: jpg CAD-Model.jpg (52.7 KB, 44 views)
powpow is offline   Reply With Quote

Old   December 21, 2012, 06:57
Default
  #2
Senior Member
 
AB
Join Date: Sep 2009
Location: France
Posts: 323
Rep Power: 21
BrolY will become famous soon enough
Close surface 1, 2 and 3.
Leave the others open in order to let the fluid flow inside your geometry.
Just create one body (fluid for example) and that should work.

I would strongly recommand to do a build topology before doing the tetra mesh.
BrolY is offline   Reply With Quote

Old   December 21, 2012, 07:12
Default
  #3
Member
 
Join Date: Dec 2012
Posts: 32
Rep Power: 13
powpow is on a distinguished road
Thank you for your fast Response!

I'll try it but one question regarding the BODY:
I have to use "material Point" - "Centroid of two Points" I think!?
Which screen locations do I have to select? On surfaces or curves? And where, do they have to be? On the left and the right wall of the camber?
powpow is offline   Reply With Quote

Old   December 21, 2012, 08:31
Default
  #4
Senior Member
 
AB
Join Date: Sep 2009
Location: France
Posts: 323
Rep Power: 21
BrolY will become famous soon enough
Centroid of 2 points is ok. You don't mind about the location, just put it in the middle of your geometry.
BrolY is offline   Reply With Quote

Old   December 21, 2012, 09:17
Default
  #5
Member
 
Join Date: Dec 2012
Posts: 32
Rep Power: 13
powpow is on a distinguished road
Thanks a lot
Ok, I've closed surface 1-3 and imported the .igs into ICEM CFD.

Then I build topology, the result is shown in the Image.

Red and blue curves are okay!
Yellow curves means that the curve is shared by only one surface and of course the running-in of the two nozzles and the tube are shared by only one surface. I hope this is no Problem?!
Attached Images
File Type: jpg build_topology.jpg (71.7 KB, 31 views)
powpow is offline   Reply With Quote

Old   December 21, 2012, 10:34
Default
  #6
Senior Member
 
AB
Join Date: Sep 2009
Location: France
Posts: 323
Rep Power: 21
BrolY will become famous soon enough
Can you share your geometry ?

What tolerance did you specify ?
What is the smallest element size of your mesh ?

If your smallest element size is bigger than the gap between two curves, then don't mind. Otherwise, that may cause trouble.
BrolY is offline   Reply With Quote

Old   December 21, 2012, 14:46
Default
  #7
Member
 
Join Date: Dec 2012
Posts: 32
Rep Power: 13
powpow is on a distinguished road
First I imported the .igs into ICEM CFD 13. Therefore I enabled "Use Version 5.1 Step Translator" and "Use healing".

Then I "Build topology" with Tolerance 1.
"Inherit Part", "Split surface at T-Connections" and "Delete unattached curves and points" were enabled.

I don't know the smallest element size of my mesh yet, since I'v never created a mesh so far. As is said, I just have to do a "simple" CFD-Simulation. I don't know yet which element size will be sufficient..

Of course I can share my .igs-File!
Attached Files
File Type: zip BA006_Basis_Drossel100.zip (68.1 KB, 2 views)
powpow is offline   Reply With Quote

Old   January 15, 2013, 06:07
Default
  #8
Member
 
Join Date: Dec 2012
Posts: 32
Rep Power: 13
powpow is on a distinguished road
So, I've created a Body called Fluid and did a Build Topology .

Then, I created the mesh as follows:

Register Mesh - Surface Mesh Setup - Surfaces: I selected all surfaces, entered my values and applied.

Register Mesh - Compute Mesh - Volume Mesh - Compute.

Then, I wanted to add 10 layers of prism:

Register Mesh - Compute Mesh - Prism Mesh.
There I selected the parts for the prism layers and clicked "ok".

Then I clicked surface mesh up, chose the surfaces of the tube and the small nozzle and applied.

Then: Register Mesh - Compute Mesh - Volume Mesh. I enabled create prism layers and computed.

I exported the result with the Register Output - Select Solver. I chose Ansys CFX and ANSYS and applied.
Then Register Output - Write Input and enabled BINARY instead of ASCII.


Then I started CFX-Pre - New case - Simulation Type: General
Click with the right mouse button on mesh - import mesh - ICEM CFD and chose the created .cfx5-file.
As you can see in the image lost inner geometry I "lost" the whole inner geometry!

I hope someone finds my mistake?
Attached Images
File Type: jpg lost_inner_geometry.jpg (88.6 KB, 22 views)
powpow 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
Reg difficulties in meshing the geometry...Urgent arunraj ANSYS Meshing & Geometry 0 August 27, 2011 00:25
2D geometry to 3D geometry Sgonzalezg ANSYS Meshing & Geometry 11 April 8, 2011 12:02
[snappyHexMesh] Trouble with stl file: surface not closed (snappyHexMesh) sfalsharif OpenFOAM Meshing & Mesh Conversion 3 April 3, 2011 06:53
[snappyHexMesh] SnappyHexMesh meshes inside and outside of an STL geometry villier OpenFOAM Meshing & Mesh Conversion 17 June 15, 2010 20:51
[GAMBIT] import terrain geometry cfdworker ANSYS Meshing & Geometry 2 May 24, 2009 22:40


All times are GMT -4. The time now is 18:14.