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

[GAMBIT] How to set up a wind tunnel with interior?

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   April 7, 2009, 16:10
Default How to set up a wind tunnel with interior?
  #1
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
Hello!

I have some huge problems with the following task: (see attachment)

I have to set up a wind tunnel (face 2), a smaller quader which has to act as interior for a smaller meshing setp (face 4) and an aerofoil in the middle.

My first problem is the substraction of the three faces.
Which steps i have to follow?

1. substract face 1 from face 4 (without retain or something?) gives then Face A
2. substract the new face A from face 2 (also without retain or something?

i think i have to set up face 4 as interior, right? do i have to do this after the substracting?


kind regards!
Attached Images
File Type: jpg Untitled-2.jpg (43.5 KB, 109 views)
Zweeper is offline   Reply With Quote

Old   April 8, 2009, 01:42
Default
  #2
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
-Substract face 4 with face 1, it generates face A
-Split face 2 with face A
You don't need to set any face as Interior
-mAx- is offline   Reply With Quote

Old   April 8, 2009, 04:43
Default
  #3
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
okay, i did it your way, but now gambit meshes the area between face 4 and face 2, and the aerofoil in the middle (face 1). the area between face 1 and face 4 remains empty.
Zweeper is offline   Reply With Quote

Old   April 8, 2009, 04:50
Default
  #4
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
hmm funny...
if you substract face4 with face1, what is the result?
-mAx- is offline   Reply With Quote

Old   April 8, 2009, 05:11
Default
  #5
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
then it works. but when i split the faces afterwards, i have the porblem i wrote in the post before.

now i can mesh every face how it should be, but when i export this file and import it into fluent, face 4 has a behaviour of a normal wall. do i have to change the boundary coniditons into fluent or gambit of face 4?

(i know how to set up the other boundary conditions like velocity inlet, walls and pressure outlet)
Zweeper is offline   Reply With Quote

Old   April 8, 2009, 05:15
Default
  #6
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
okay wait, now the mesh from face 2 is under the mesh from face 4 and face 1
Zweeper is offline   Reply With Quote

Old   April 8, 2009, 05:33
Default
  #7
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
ok I assume the face 4 and face 1 are right substracted (I call this face A).
Try to split face 4 with the outer edges from A (rectangle)
Normally you shoul have 2 faces on the same location (face A and the face resulting from the split)
Delete the face resulting from the split.
All the edges should be right connected, but you can go and connect all edges (as security)
-mAx- is offline   Reply With Quote

Old   April 8, 2009, 05:54
Default
  #8
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
okay, you mean i should use the "split face" option, select face 4 by "face", select "edges (virtual)" by "split with" and then i select the 4 edges from face 4, right?

when i do this, gambit shows the following error meessage:

face.4 could not be split with edge... which is coincident with the face boundary. Such a split may result in a degenerate geometry.



sorry, i know the "basics" form gambit, but for this project i have to to it with the inner face 4 and i have so huge problems with this assignment as you can see
Zweeper is offline   Reply With Quote

Old   April 8, 2009, 06:33
Default
  #9
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
Quote:
Originally Posted by Zweeper View Post
okay, you mean i should use the "split face" option, select face 4 by "face", select "edges (virtual)" by "split with" and then i select the 4 edges from face 4, right?

when i do this, gambit shows the following error meessage:

face.4 could not be split with edge... which is coincident with the face boundary. Such a split may result in a degenerate geometry.
wait... you must split face 2 with the 4 edges from face A (face 4 shouldn t exist anymore as you substrated it with face 1)
send me the dbs file
-mAx- is offline   Reply With Quote

Old   April 9, 2009, 05:34
Default
  #10
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
on your email adress?
Zweeper is offline   Reply With Quote

Old   April 9, 2009, 07:20
Default
  #11
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
upload it on www.rapidshare.com
-mAx- is offline   Reply With Quote

Old   April 9, 2009, 07:31
Default
  #12
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
okay, here it is:

http://rapidshare.com/files/219227546/working.rar.html
Zweeper is offline   Reply With Quote

Old   April 9, 2009, 09:31
Default
  #13
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
ok I don't understand why it has failed with my previous method, but anyway you can handle your problem followings:
*substract face2 with face 1
*then split the face 2 (which is the result of the previous operation) with face 4
That's it

-mAx- is offline   Reply With Quote

Old   April 9, 2009, 11:34
Default
  #14
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
yes, this works! thanks a lot!!!
Zweeper is offline   Reply With Quote

Old   December 20, 2009, 14:12
Default
  #15
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
okay, now i have the SAME problem, just for 3D.

I tried the same to solve this issue, but seems like that something with the mesh IN the interior doesn't fix. when i say fluent to show me "just the velocity vectors of the interior", it shows me just vectors on the wall of the interior.
The interior is not filled with vectors. I guess that this is wrong, but i don't know what my mistake is.

any ideas/help for my problems?

Kind regards!
Zweeper is offline   Reply With Quote

Old   December 20, 2009, 14:16
Default
  #16
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
post a picture
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   December 20, 2009, 14:36
Default
  #17
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
okay, picture 1 shows my gambit work. the round hemisphere is the interior.
the two bricks in the middle are the walls.

picture 2 shows the bricks (lorry) in fluent. seems like everything is all right!

picture 3 shows now the interior and i have just vectors on the surface of it. is this wrong? i think so, but what could be wrong?


when i want to see the vectors of the standard interior then it shows me all vectors, i mean, then it is okay.
Attached Images
File Type: jpg 1.JPG (51.1 KB, 32 views)
File Type: jpg 2.JPG (25.9 KB, 32 views)
File Type: jpg 3.jpg (61.1 KB, 30 views)
Zweeper is offline   Reply With Quote

Old   December 20, 2009, 14:45
Default
  #18
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
in gambit, click on the icon (next to examine mesh)
you will have blue colors instead of green (and pink for the hemisphere).
post the picture.
You should have difficulties to mesh your domain because of the small angle between the big brick and the hemisphere.
What should be th functionnality of the hemispherein comparison of the big brick?
Create a XY plane, and display any variable (velocity for instance), and post also the picture
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   December 20, 2009, 15:00
Default
  #19
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
okay, here is the picture with the specific color mode.

the task of the hemisphere is... its just that we had this more or less in the lesson. the teacher said to us we should create an interior (what sounds logical) and he did it with a hemisphere.

maybe its better to take a big box instead of the hemisphere?
Attached Images
File Type: jpg 4.JPG (40.4 KB, 15 views)
Zweeper is offline   Reply With Quote

Old   December 20, 2009, 15:04
Default
  #20
Member
 
smith
Join Date: Apr 2009
Posts: 75
Rep Power: 16
Zweeper is on a distinguished road
but maybe this is also a problem:

when i mesh the big box, this error message appears (attachment)

when i mesh it a second time, gambit refines the mesh and everything seems like okay. is this a problem? i'm not sure with this.
Attached Images
File Type: jpg Capture.JPG (36.5 KB, 18 views)
Zweeper 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
Simulating a Göttingen type wind tunnel in FLUENT Chris FLUENT 3 December 4, 2006 18:33
Virtual Wind Tunnel in FLUENT ND FLUENT 0 April 7, 2006 08:43
Env variable not set gruber2 OpenFOAM Installation 5 December 30, 2005 05:27
Wind tunnel modeling Pandu CFX 3 May 19, 2003 22:49
Wind Tunnel Website now online Mike Worthey Main CFD Forum 0 June 6, 2000 03:27


All times are GMT -4. The time now is 01:42.