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

Meshing Sudden Contraction and Expansion

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   January 19, 2017, 12:30
Default
  #21
New Member
 
parham
Join Date: Oct 2015
Posts: 24
Rep Power: 10
mk091088 is on a distinguished road
Thank you Max for your help. I was able to mesh my geometry. Just for curiosity, Is there any way to mesh Face 2 by Quad map instead of Quad pave?, because it can significantly improve my calculation downstream pipe (volume 2). I was only able to mesh Face 1 with Quad map (since it is annulus face).
Attached Images
File Type: png schematic.png (27.5 KB, 12 views)
mk091088 is offline   Reply With Quote

Old   January 20, 2017, 01:33
Default
  #22
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
yes with o-grid
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   January 20, 2017, 12:30
Default
  #23
New Member
 
parham
Join Date: Oct 2015
Posts: 24
Rep Power: 10
mk091088 is on a distinguished road
Dear Max,

I tried to use O-ring method based on another Thread that you suggested, here is the procedure which, unfortunately, failed:

First, I created a cube inside a circle, I chose four vertexes on the circle's edges, connect corner of cube to four vertexes on circle. I separated circle edges into four edges.now, I have five faces, including cube. Idid the same on the other face wich has a larger diameter at contraction point. When I reapet the procedure, as you suggested before, to create a surface inside upstream volume by edges, an error occurred. I attached to you geometry. What should I do in this case.
Attached Images
File Type: jpg o-ring.jpg (76.9 KB, 14 views)
mk091088 is offline   Reply With Quote

Old   January 23, 2017, 01:24
Default
  #24
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
alright I understand you cannot create the surfaces parallel to the cylinder axis, right?
Did you split the cylinder surface (smallest diameter of the annulus volume)?
__________________
In memory of my friend Hervé: CFD engineer & freerider

Last edited by -mAx-; January 23, 2017 at 07:48.
-mAx- is offline   Reply With Quote

Old   January 23, 2017, 07:42
Default
  #25
New Member
 
parham
Join Date: Oct 2015
Posts: 24
Rep Power: 10
mk091088 is on a distinguished road
Exactly, I cannot create surface from edges parallel to the pipe axis. I also splited small circle into four arc edges. Now in the small circle, I have 5 faces, including one cube.
mk091088 is offline   Reply With Quote

Old   January 23, 2017, 07:54
Default
  #26
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
As I mentionned, you need to split the cylinder surface with circle's vertices
Capture.JPG
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   January 23, 2017, 08:49
Default
  #27
New Member
 
parham
Join Date: Oct 2015
Posts: 24
Rep Power: 10
mk091088 is on a distinguished road
As I told you, I have separated the circle from vertexes. Still not working.
mk091088 is offline   Reply With Quote

Old   January 23, 2017, 08:52
Default
  #28
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
how did you create the lines parallel to the axis?
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   January 23, 2017, 10:09
Default
  #29
New Member
 
parham
Join Date: Oct 2015
Posts: 24
Rep Power: 10
mk091088 is on a distinguished road
I created two cubes inside circles. I connected vertexes on first and second circles. Also, each vertex on cube to similar one in the second cube. I simply used create edges from vertexes. But, the problem is that when I want to create surface from edges.
mk091088 is offline   Reply With Quote

Old   January 23, 2017, 10:49
Default
  #30
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
If you "simple" create Lines like that; then you will not be able to Split the Volume. That s Why I suggested to Split the surface with vertex


Sent from my iPhone using CFD Online Forum mobile app
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   January 25, 2017, 16:30
Default
  #31
New Member
 
parham
Join Date: Oct 2015
Posts: 24
Rep Power: 10
mk091088 is on a distinguished road
Here is the procedure that I did:

As you told, I created four vertexes on circle, then, I have splited face (circle) from four vertexes. So, the result would be a cube inside circle. Eventually, I have 5 faces, see pic 1. I did the same for the second circle (see pic 2).
I have linked each vertex on the first circle to the similar one on the second circle (see pic 3). I tried to create face from edges, but still unsuccessful (see pic 4). Something else that I should know?
Attached Images
File Type: png pic 1.png (21.2 KB, 10 views)
File Type: jpg pic 2.jpg (34.2 KB, 10 views)
File Type: jpg pic 3.jpg (40.9 KB, 9 views)
File Type: jpg pic 4.jpg (60.0 KB, 7 views)
mk091088 is offline   Reply With Quote

Old   January 26, 2017, 01:28
Default
  #32
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
No,
your splits are wrong.
What you proposed at #23 was good.
You only didn't get my point regarding the splits on the cylinder surface.
For that I post a picture: I split the blue surface with both vertices (red)
Capture1.JPG
Capture.JPG
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   January 26, 2017, 16:54
Default
  #33
New Member
 
parham
Join Date: Oct 2015
Posts: 24
Rep Power: 10
mk091088 is on a distinguished road
Excuse me Max, but I do not think you get my problem. I understand that I should split the blue surface from red vertexes in your shared photo. My problem is not to separate two volumes. The big problem is :
When I created four vertexes on small circles in both sides (circles 1 and 2), then created edges 1,2,3,4.
I created surfaces from edge 1, edge 3, edge 5, and edge 9. I created also surface from edges 3, 4, edge 6, and 10 and so on (see picture 1). I separated volume from created surfaces to create two volumes. So, the step you suggested is not needed. Question: How can I make a Quad map in picture 3?
Attached Images
File Type: jpg picture 1.jpg (58.9 KB, 3 views)
File Type: jpg picture 2.jpg (44.5 KB, 1 views)
File Type: png picture 3.png (73.5 KB, 3 views)
mk091088 is offline   Reply With Quote

Old   January 27, 2017, 00:56
Default
  #34
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
you cannot because this surface is not meshable with map.
You didn't split it as it should be.
The 4 corners of your square don't have to lie on the circle.
I previously mentionned you that this split was not correct.
See your post #23, where you displayed your previous split (and it was good)
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- 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



All times are GMT -4. The time now is 05:08.