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

[GAMBIT] Boundary layer direction

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

Reply
 
LinkBack Thread Tools Display Modes
Old   November 7, 2012, 09:39
Default Boundary layer direction
  #1
New Member
 
Join Date: Oct 2012
Posts: 14
Rep Power: 4
Markus is on a distinguished road
Hello,

I have a very frustrating problem and i read through so many posts but nothing works.

I have substracted my cubic like geometry from a big cube for the computational domain and now want to create a boundary layer on the inner surface of course pointing to the fluid. But gambit always points it inside ?!?!!

I have read about using the middle button of the mouse, double left klick and to use the list and add the same face until it points the right way.

But it just doesn't work.. :-(


Also i tried defining the space in between as fluid and the structure as solid..

I would appreciate any type of help a lot! Pleeease help me!

Thanks!

Last edited by Markus; November 7, 2012 at 09:58.
Markus is offline   Reply With Quote

Old   November 8, 2012, 05:43
Default
  #2
Senior Member
 
Marion
Join Date: Jul 2012
Location: France
Posts: 122
Rep Power: 5
Marion is on a distinguished road
Hi Markus,

Do you have volumes other than your fluid domain in Gambit?
Can you add a picture, it would be easier to understand...

Marion.
Marion is offline   Reply With Quote

Old   November 8, 2012, 07:54
Default
  #3
New Member
 
Join Date: Oct 2012
Posts: 14
Rep Power: 4
Markus is on a distinguished road
Hi Marion,

Thank you for answering. I think i only have the fluid volumes. (see pictures 3 and 4)

The geometry in the middle is the thing i want to put in the flow. then thought its good to make a close region for the boundary layer and a fine mesh and then i wanted to fill the rest of the computational domain (volume2) using a size function.

best,
Markus
Attached Images
File Type: jpg pic1.jpg (82.7 KB, 19 views)
File Type: jpg pic2.jpg (88.0 KB, 12 views)
File Type: jpg pic3.jpg (88.4 KB, 12 views)
File Type: jpg pic4.jpg (90.9 KB, 13 views)
Markus is offline   Reply With Quote

Old   November 8, 2012, 09:32
Default
  #4
Member
 
Tamil Nadu
Join Date: Oct 2012
Posts: 44
Rep Power: 4
nkme2007 is on a distinguished road
Hi Markus,

Mine is also similar problem, I feel. I want to model a building in GAMBIT 3D. Finally, aim of my project is to simulate the temperatures of the walls of building when water flows through pipes inserted in the ceiling (using Ansys Fluent). Is it possible to solve??
nkme2007 is offline   Reply With Quote

Old   November 8, 2012, 11:12
Default
  #5
Senior Member
 
Marion
Join Date: Jul 2012
Location: France
Posts: 122
Rep Power: 5
Marion is on a distinguished road
Quote:
Originally Posted by Markus View Post
Hi Marion,

Thank you for answering. I think i only have the fluid volumes. (see pictures 3 and 4)

The geometry in the middle is the thing i want to put in the flow. then thought its good to make a close region for the boundary layer and a fine mesh and then i wanted to fill the rest of the computational domain (volume2) using a size function.

best,
Markus
Markus,

Try to split your volumes first, it will be easier to control the mesh.

Is it hollow in the middle? or do you still have a volume there?

If you want, you can attach your model and I'll have a try.

Marion.
Marion is offline   Reply With Quote

Old   November 8, 2012, 11:24
Default
  #6
New Member
 
Join Date: Oct 2012
Posts: 14
Rep Power: 4
Markus is on a distinguished road
i think it is hollow... :-)
That would be very nice of you, thanks!


Markus
Attached Files
File Type: zip satsat2zip.zip (51.3 KB, 3 views)
Markus is offline   Reply With Quote

Old   November 9, 2012, 04:17
Default
  #7
Senior Member
 
Marion
Join Date: Jul 2012
Location: France
Posts: 122
Rep Power: 5
Marion is on a distinguished road
Hi,
I've just had a look, and I got the same issue on your original model.
But I confirm my advice: split your volume into smaller domains.
I split it in 8, and I used BL on edges it worked very well
As it is a simple geometry, you can even split it on each side of your small parallelepipeds.
I hope this helps,
Marion.
Marion is offline   Reply With Quote

Old   November 9, 2012, 04:18
Default
  #8
Senior Member
 
Marion
Join Date: Jul 2012
Location: France
Posts: 122
Rep Power: 5
Marion is on a distinguished road
Quote:
Originally Posted by Marion View Post
Hi,
I've just had a look, and I got the same issue on your original model.
But I confirm my advice: split your volume into smaller domains.
I split it in 8, and I used BL on edges it worked very well
As it is a simple geometry, you can even split it on each side of your small parallelepipeds.
I hope this helps,
Marion.

Here are some snapshots.
Attached Images
File Type: jpg Image1.jpg (36.5 KB, 10 views)
File Type: jpg Image2.jpg (30.1 KB, 7 views)
Marion is offline   Reply With Quote

Old   November 9, 2012, 04:53
Default
  #9
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,905
Blog Entries: 6
Rep Power: 38
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
boudary layer is good option, but should be used where it is appliable. Dividing into small volume is the best approach for hexa mshing and mesh control in particular area. For example see this thread Boundary layer mesh & map mesh in rectangular ribbed channel and this video: http://www.youtube.com/watch?v=Gub1Kbcup2k&feature=plcp
Far is offline   Reply With Quote

Old   November 9, 2012, 05:38
Default
  #10
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,905
Blog Entries: 6
Rep Power: 38
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
How many cubes are there? do you want to mesh inside the small cube, where small sheets are present? Is it part of Fluid?

Do you have access to ICEM?
Far is offline   Reply With Quote

Old   November 9, 2012, 12:14
Default
  #11
New Member
 
Join Date: Oct 2012
Posts: 14
Rep Power: 4
Markus is on a distinguished road
hi

Thank you very much for all the advice, i will try it out.


Markus
Markus is offline   Reply With Quote

Old   November 9, 2012, 13:10
Default
  #12
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,905
Blog Entries: 6
Rep Power: 38
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
There are three cubes and some protrusion (six in total)? volume inside the small cube (cube) is hollow? and also volume inside six small box is also hollow?
Far is offline   Reply With Quote

Old   November 9, 2012, 14:09
Default
  #13
New Member
 
Join Date: Oct 2012
Posts: 14
Rep Power: 4
Markus is on a distinguished road
The geometry which represents the solid is the big cube and the six cubes on the surfaces, they are not fluid.

Its a model of a cubesat with thrusters (6 small cubes ) for an underwater test.

I did try by splitting, but it also looks strange now
Attached Images
File Type: jpg pic5.jpg (96.3 KB, 7 views)
Markus is offline   Reply With Quote

Old   November 9, 2012, 14:22
Default
  #14
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,905
Blog Entries: 6
Rep Power: 38
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
like this.....
Attached Images
File Type: jpg room1.jpg (66.9 KB, 13 views)
File Type: gif room2.gif (41.6 KB, 17 views)
Far is offline   Reply With Quote

Old   November 12, 2012, 06:01
Default
  #15
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,905
Blog Entries: 6
Rep Power: 38
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
I hope this is helpful to you.
Attached Files
File Type: zip room.zip (25.0 KB, 5 views)
Far 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
Boundary layer in a pipe Clementhuon OpenFOAM Native Meshers: snappyHexMesh and Others 6 March 12, 2012 13:41
simulation of stokes boundary layerr (oscillating boundary layer) beguxa FLUENT 1 December 10, 2011 05:30
direction of boundary layer in gambit Ilu FLUENT 7 October 16, 2008 03:20
Help!!!: Direction / Normal of Boundary Layer JP FLUENT 0 September 9, 2008 18:16
New topic on same subject - Flow around race car Tudor Miron CFX 15 April 2, 2004 06:18


All times are GMT -4. The time now is 22:44.