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

[ICEM] Hexa mesh fine to coarse transition

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

Like Tree1Likes
  • 1 Post By bluebase

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   January 23, 2020, 02:46
Default Hexa mesh fine to coarse transition
  #1
Ram
New Member
 
Ramprasad
Join Date: Nov 2011
Posts: 4
Rep Power: 14
Ram is on a distinguished road
Hi,

How to make a transition in Hexa mesh from fine to coarse?

Example: A common edge would have 12 elements one side and 8 elements on other side.
Ram is offline   Reply With Quote

Old   January 23, 2020, 04:15
Default
  #2
Senior Member
 
Gert-Jan
Join Date: Oct 2012
Location: Europe
Posts: 1,836
Rep Power: 27
Gert-Jan will become famous soon enough
try the tutorials.
Gert-Jan is offline   Reply With Quote

Old   February 14, 2020, 05:28
Default Could not find anything in tutorials
  #3
Ram
New Member
 
Ramprasad
Join Date: Nov 2011
Posts: 4
Rep Power: 14
Ram is on a distinguished road
To be more precise....I have two 3D blocks to be merged. One of the parallel edge on the interface has 40 and 20 elements. Now when I merge both, I need a transition between both blocks and require only hexa elements.
Ram is offline   Reply With Quote

Old   February 14, 2020, 05:38
Default
  #4
Senior Member
 
Gert-Jan
Join Date: Oct 2012
Location: Europe
Posts: 1,836
Rep Power: 27
Gert-Jan will become famous soon enough
You cannot do this. 40 and 20 simply don't match. You either need to increase one or decrease the other. Alternatively:
- you need a block coming from the side. But this is too difficult to explain in words. You need to share pictures.
- create an interface in the cfd package that you use.
Gert-Jan is offline   Reply With Quote

Old   February 14, 2020, 06:59
Default
  #5
Senior Member
 
Sebastian Engel
Join Date: Jun 2011
Location: Germany
Posts: 566
Rep Power: 20
bluebase will become famous soon enough
Hi Ram,

as Gert-Jan said, the blocking structure always has to have the same number of nodes between neighbouring blocks.

If your solver can deal with hanging nodes, than you might consider using refinement levels with will increase the number of elements in a block by a given factor. However, in the underlying blocking structure still has the explained interdependency.

Another option are interface boundaries. In a lot of cfd solvers such interfaces do not need to be conformal. One might consider hanging nodes as a special case of interfaces.

Finally, if you really cannot workout how to get the desired mesh density you can try a technique called nesting:
nesting.jpg
Here you create c-grid on one side of the "interface". However, this comes at the cost of somewhat misaligned elements (element faces should be aligned with the flow to reduce numeric diffusion). Moreover, you mostly have to create these structures manually.
An additionally nice feature might be the possibility fully resolve to 1-to-3 ratios of refinement levels with this nesting strategy (There is some info spread in this forum). However, the automatic nesting in this case creates tiny nestings for each original element layers... Again this might lead to undesired numerical diffusion.

Best regards,
Sebastian
aero_head likes this.
bluebase is offline   Reply With Quote

Reply

Tags
hexa, transition

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
foam-extend-4.1 release hjasak OpenFOAM Announcements from Other Sources 19 July 16, 2021 05:02
Gambit problems Althea FLUENT 22 January 4, 2017 03:19
interpolate results from fine to coarse mesh??? ndabir FLUENT 1 July 29, 2013 22:48
From a fine to a coarse mesh Nereus Main CFD Forum 0 June 11, 2012 09:57
Icemcfd 11: Loss of mesh from surface mesh option? Joe CFX 2 March 26, 2007 18:10


All times are GMT -4. The time now is 07:51.