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

[GAMBIT] 2D ellipse in rectangular domain

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 24, 2010, 03:08
Default [GAMBIT] 2D ellipse in rectangular domain
  #1
Senior Member
 
Pavan
Join Date: May 2009
Location: Melbourne
Posts: 101
Rep Power: 8
rieuk is on a distinguished road
Hi guys, I'm wondering how to create the mesh in Gambit as shown in the figures attached. Particularly how to get the curvilinear grid lines from the surface of the ellipse to the outer circle.

Creating nodes on the ellipse and the circle then meshing them simply creates nodes following straight lines from the circle to the ellipse resulting in skewed cells on the ellipse surface.
Attached Images
File Type: png mesh1.PNG (20.8 KB, 60 views)
File Type: png mesh2.PNG (22.2 KB, 50 views)
rieuk is offline   Reply With Quote

Old   February 26, 2010, 02:27
Default
  #2
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,992
Rep Power: 30
-mAx- will become famous soon enough
try to attach a Boundary Layer on the ellipse with lot's of layers
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   February 26, 2010, 03:46
Default
  #3
Senior Member
 
Pavan
Join Date: May 2009
Location: Melbourne
Posts: 101
Rep Power: 8
rieuk is on a distinguished road
Thanks for the reply, but creating a boundary layer on the ellipse simply creates nodes coming out in straight lines.

I need some kind of way to create intermediate mesh lines between the ellipse and circle to gradually release the ellipse into the circle.

I've asked a lot of people who were supposedly very good using GAMBIT and noone has any idea of what I'm talking about much less what I want to achieve.
rieuk is offline   Reply With Quote

Old   February 26, 2010, 04:54
Default
  #4
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,992
Rep Power: 30
-mAx- will become famous soon enough
ok you don't want normal lines...
Then you have to enforce gambit meshing your domain with curved lines.
You have to plit your domain with those curved lines.
In the pictures you can see my splits (blue lines), but maybe it is not what you want...
Attached Images
File Type: jpg ellipse.jpg (91.1 KB, 38 views)
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   February 26, 2010, 06:38
Default
  #5
Senior Member
 
Pavan
Join Date: May 2009
Location: Melbourne
Posts: 101
Rep Power: 8
rieuk is on a distinguished road
Hey Max, thanks for having a go at it and yea I can see your blue splits (4 of them) - interesting approach and I might go with it. However it doesn't exactly apply the condition that the grid lines come out from the ellipse exactly normal at every point which the mesh in the original pics I posted seem to do...
rieuk is offline   Reply With Quote

Old   February 26, 2010, 07:46
Default
  #6
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,992
Rep Power: 30
-mAx- will become famous soon enough
My splits are done at random. Splitting with right ellipses-arcs, and at the right locations, will give you more accurate grid lines.
Also you may split your domain with another ellipse (bigger and surrounding your initila ellipse --> like a transition between your first ellipse and you circle). It will be more accurate.
Anyway you cannot expect meshing your domain on the fly without any splits.
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   October 7, 2010, 07:55
Default
  #7
New Member
 
Join Date: Oct 2010
Posts: 7
Rep Power: 6
dreft is on a distinguished road
I´m meshing a elipse like you , but I need a Boundary layer ,did you use the boundary layer¿?How do you mesh it ¿?
dreft is offline   Reply With Quote

Old   October 7, 2010, 08:46
Default
  #8
Senior Member
 
Pavan
Join Date: May 2009
Location: Melbourne
Posts: 101
Rep Power: 8
rieuk is on a distinguished road
I used the technique suggested by -MaX-. It's not exactly a conformal mesh but it works very well if you do it carefully. No I didn't use any 'boundary layer' but my mesh was naturally highly resolved in the boundary layer...
rieuk is offline   Reply With Quote

Old   October 7, 2010, 08:52
Default
  #9
New Member
 
Join Date: Oct 2010
Posts: 7
Rep Power: 6
dreft is on a distinguished road
and how did you mesh the part between the elipse and the circle¿?
I did a succesive ratio =1 and the same intervals in the elipse than in the circle.I thought that if the number of intervals grow up , maybe the boundary layer will be ok,but i´m not sure.
Thanks in advance.
dreft 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
Default domain jaho CFX 5 February 16, 2014 01:00
2D rotating ellipse (domain interface??) Kambusha CFX 38 May 19, 2012 07:10
CFX Solver Memory Error mike CFX 1 March 19, 2008 08:22
BlockMesh for a rectangular domain with curved bottom surface segersson OpenFOAM Native Meshers: blockMesh 0 April 17, 2006 14:11
Import a rectangular domain into CFX 5.7 from ICEM SKLam CFX 9 March 8, 2006 01:47


All times are GMT -4. The time now is 19:57.