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

[ICEM] suggestion for blocking strategy and meshing a corner

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

Like Tree11Likes

Reply
 
LinkBack Thread Tools Display Modes
Old   October 31, 2013, 08:44
Default suggestion for blocking strategy and meshing a corner
  #1
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Hello

I am trying to mesh a converging channel with a slender obstacle inside it. (you can see the geometry in the attachment)

I have already used split command to split the initial block as you can also see in the attachment.

This way, I have managed to get an initial mesh which is not so bad, but I can see irregularities in triangular block which is shown with a star in the picture.

My question is how can I mesh the triangular block in a better way? Is something wrong with my blocking strategy?


thanks in advance

regards
Attached Images
File Type: jpg geometry.JPG (48.8 KB, 44 views)
File Type: jpg split.JPG (92.2 KB, 44 views)
File Type: jpg initial-mesh.jpg (94.2 KB, 49 views)
Daniel_Khazaei is offline   Reply With Quote

Old   October 31, 2013, 12:43
Default
  #2
Member
 
Kevin Hoopes
Join Date: Oct 2010
Posts: 40
Rep Power: 7
khoopes is on a distinguished road
You could try a Y-Block for that area. Search the ICEM help for y-block and it shows the details.
Daniel_Khazaei likes this.
khoopes is offline   Reply With Quote

Old   November 1, 2013, 06:41
Default
  #3
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Quote:
Originally Posted by khoopes View Post
You could try a Y-Block for that area. Search the ICEM help for y-block and it shows the details.
I have tried your suggestion (attachment)

using Y-Block has made an unnecessary node density in a region which you can see in the attachment.

furthermore, I have tried this mesh with fluent and the solution was diverged. (I could get convergence with my old mesh)

Am I doing something wrong here?

thanks in advance
Attached Images
File Type: jpg 1.jpg (99.2 KB, 46 views)
File Type: jpg 2.jpg (94.0 KB, 42 views)
Daniel_Khazaei is offline   Reply With Quote

Old   November 1, 2013, 10:26
Default
  #4
Member
 
Kevin Hoopes
Join Date: Oct 2010
Posts: 40
Rep Power: 7
khoopes is on a distinguished road
The elements there do look like they are of pretty poor quality. I think you could move the vertex at the center of the Y to straighten them up. I would use the ICEM mesh metrics.

Why don't you want to use your first mesh? How does the simulation compare to experiment? Are you planning on adding near wall refinement later?
Daniel_Khazaei likes this.
khoopes is offline   Reply With Quote

Old   November 1, 2013, 10:42
Default
  #5
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Quote:
Originally Posted by khoopes View Post
The elements there do look like they are of pretty poor quality. I think you could move the vertex at the center of the Y to straighten them up. I would use the ICEM mesh metrics.

Why don't you want to use your first mesh? How does the simulation compare to experiment? Are you planning on adding near wall refinement later?
Actually near wall refinement is the main reason which leads me to change my older mesh.

This geometry is fluid part of fluid-solid interaction problem, so I do not have a separate results to check for.

The paper I am working on it uses a time step of 0.1 sec that leads me to think that they have used a coarse mesh. It's a benchmark case to validate a coupling algorithm.

can you tell me how can I add wall refinement or is there any tutorial for that?

thank in advance
Daniel_Khazaei is offline   Reply With Quote

Old   November 1, 2013, 11:13
Default
  #6
Member
 
Kevin Hoopes
Join Date: Oct 2010
Posts: 40
Rep Power: 7
khoopes is on a distinguished road
The hex mesh will be really easy to add near wall refinement, you will just change the edge spacing, making sure to propagate your changes to all parallel edges. Tutorial 1 step 6, and Tutorial 2 "Refine the Mesh using Edge Parameters" go over it. These section numbers correspond to the ICEM 14.5.7 help.
Daniel_Khazaei likes this.
khoopes is offline   Reply With Quote

Old   November 2, 2013, 12:30
Default
  #7
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Quote:
Originally Posted by khoopes View Post
The hex mesh will be really easy to add near wall refinement, you will just change the edge spacing, making sure to propagate your changes to all parallel edges. Tutorial 1 step 6, and Tutorial 2 "Refine the Mesh using Edge Parameters" go over it. These section numbers correspond to the ICEM 14.5.7 help.
I am trying to produce a mesh like the one in the attachment, is it possible in ICEM?
Attached Images
File Type: jpg new.jpg (65.3 KB, 44 views)
Daniel_Khazaei is offline   Reply With Quote

Old   November 4, 2013, 16:54
Default
  #8
Member
 
Cesar
Join Date: Nov 2012
Location: Guanajuato, México
Posts: 78
Rep Power: 6
cesarcg is on a distinguished road
Send a message via Skype™ to cesarcg
Sure it is possible using the Y-Block and adjusting the vertices of the blocking as convenient, as suggested previously by @khoopes. However, that strategy will impose a very dense distribution in some undesired areas. In my opinion, I think it is possible to mesh the geometry without the need of that Y-Block.

Regards.
Daniel_Khazaei likes this.
cesarcg is offline   Reply With Quote

Old   November 5, 2013, 12:33
Default
  #9
Super Moderator
 
diamondx's Avatar
 
Ghazlani M. Ali
Join Date: May 2011
Location: Canada
Posts: 1,291
Blog Entries: 23
Rep Power: 20
diamondx will become famous soon enough
you need a y-grid. yo cannot do that in 2d, so create your blocking, extrude 3d, convert that block into a y-grid, and convert the hole blocking to 2d again ! i hope i was clear !
Daniel_Khazaei likes this.
__________________
Regards,
New to ICEM CFD, try this document --> http://goo.gl/G2gkE
Ali
diamondx is offline   Reply With Quote

Old   November 6, 2013, 10:04
Default
  #10
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Quote:
Originally Posted by diamondx View Post
you need a y-grid. yo cannot do that in 2d, so create your blocking, extrude 3d, convert that block into a y-grid, and convert the hole blocking to 2d again ! i hope i was clear !
Thanks for the tip, but would you please tell me is there any difference between Y-block and y-grid?


regards
Daniel_Khazaei is offline   Reply With Quote

Old   November 6, 2013, 10:56
Default
  #11
Super Moderator
 
diamondx's Avatar
 
Ghazlani M. Ali
Join Date: May 2011
Location: Canada
Posts: 1,291
Blog Entries: 23
Rep Power: 20
diamondx will become famous soon enough
my mistake, I wanted to say y-block !
Daniel_Khazaei likes this.
__________________
Regards,
New to ICEM CFD, try this document --> http://goo.gl/G2gkE
Ali
diamondx is offline   Reply With Quote

Old   November 6, 2013, 11:11
Default
  #12
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Quote:
Originally Posted by diamondx View Post
my mistake, I wanted to say y-block !
I have tried Y-block method as khoopes suggested, but it will produce an unnecessary mesh density in the regions near the Y shape. ( as you can see in the 3rd post )
Daniel_Khazaei is offline   Reply With Quote

Old   November 6, 2013, 15:14
Default
  #13
Super Moderator
 
diamondx's Avatar
 
Ghazlani M. Ali
Join Date: May 2011
Location: Canada
Posts: 1,291
Blog Entries: 23
Rep Power: 20
diamondx will become famous soon enough
have you tried something just like this :

__________________
Regards,
New to ICEM CFD, try this document --> http://goo.gl/G2gkE
Ali
diamondx is offline   Reply With Quote

Old   November 6, 2013, 16:42
Default
  #14
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Thanks for the deep recommendation man

I will try that and come back to you.
Daniel_Khazaei is offline   Reply With Quote

Old   November 7, 2013, 07:55
Default
  #15
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Quote:
Originally Posted by diamondx View Post
have you tried something just like this :
I tried to mesh like the picture you have provided, but when I test the mesh in fluent the solution does not converge. (huge oscillation in residual)

I have attached the geometry here, would please tell me how do you deal with geometries like this?
Attached Files
File Type: zip fluid.zip (1.5 KB, 4 views)
Daniel_Khazaei is offline   Reply With Quote

Old   November 7, 2013, 10:39
Default
  #16
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,971
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
try this...and let me know if it is ok or not
Attached Files
File Type: zip fluid.zip (13.7 KB, 10 views)
Daniel_Khazaei likes this.
Far is offline   Reply With Quote

Old   November 7, 2013, 13:32
Default
  #17
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Quote:
Originally Posted by Far View Post
try this...and let me know if it is ok or not
Can you tell me how did you create a boundary layer mesh around the block?

I only need that for bottom walls and I have done a few merged command to get a mesh like the one in the attachment. ( I done it on your files )

However I have a few problems on the merged edges. After the merging process I have negative quality, and fluent reports 0 orthogonal quality.
Attached Images
File Type: jpg Capture.jpg (97.1 KB, 25 views)
Daniel_Khazaei is offline   Reply With Quote

Old   November 7, 2013, 19:43
Default
  #18
Member
 
Sheng
Join Date: Jun 2011
Posts: 58
Rep Power: 6
micro11sl is on a distinguished road
Hi,
I just find I have done something similar before, see my attachment, extracting from one of my report.

Regards
Sheng
Attached Images
File Type: jpg 1.jpg (46.7 KB, 37 views)
File Type: png 2.png (42.7 KB, 29 views)
File Type: png 3.png (62.9 KB, 28 views)
File Type: jpg 4.jpg (48.7 KB, 25 views)
File Type: png 5.png (42.8 KB, 26 views)
micro11sl is offline   Reply With Quote

Old   November 7, 2013, 20:08
Default
  #19
Senior Member
 
Daniel
Join Date: Mar 2013
Posts: 177
Rep Power: 9
Daniel_Khazaei will become famous soon enough
Quote:
Originally Posted by micro11sl View Post
Hi,
I just find I have done something similar before, see my attachment, extracting from one of my report.

Regards
Sheng
would please tell me how did you managed to get the final mesh? (first image)
Daniel_Khazaei is offline   Reply With Quote

Old   November 7, 2013, 23:51
Default
  #20
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,971
Blog Entries: 6
Rep Power: 39
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
Steps are:

1. Make the initial block

2. Make one horizontal spilt

3. Make 4 vertical splits. One is at the end of ramp and other few units before it.

4. Delete the block in lower right corner

5. merge vertices at the end of ramp and now you have wedge block

6. Go to y-block command apply on it

7. Make associations

8. Again select all blocks, faces on two sides of your geometry (symmetry) and other faces where you don't want O-grid

9. Smooth mesh in wedge block, but be careful using parameters for smoothing.
Daniel_Khazaei likes this.
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
[ANSYS Meshing] Blocking and Meshing Strategy for an open flow domain over backward facing ramp Crank-Shaft ANSYS Meshing & Geometry 0 January 11, 2013 06:48
[ICEM] Meshing strategy for 3D sharp point D-willism ANSYS Meshing & Geometry 22 October 15, 2012 06:06
meshing strategy for IC engine. Upendra Main CFD Forum 1 September 30, 2012 02:32
[ANSYS Meshing] Meshing strategy for External Flows Hybrid ANSYS Meshing & Geometry 0 January 24, 2012 15:27
meshing strategy for tight fit. jemteo CFX 4 August 10, 2004 02:30


All times are GMT -4. The time now is 07:02.