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

[ICEM] Structured multi-block mesh non-smooth

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 11, 2022, 03:38
Default Structured multi-block mesh non-smooth
  #1
New Member
 
S Ram Kumar
Join Date: Jan 2019
Location: India
Posts: 12
Rep Power: 7
ramkr is on a distinguished road
Hello,
I am working with ICEM-CFD for structured grid generation and output to CFL3D solver format.

Shown below is the rectangular 2D domain of a no-slip viscous plate in the bottom horizontal with a wedge like shock generator (SG) in the middle of the domain.

Currently, I have split the domain into 4 blocks as shown. The issue I am facing is the grid lines originating from the sharp leading edge of the SG are splitting and diverging into a triangular non-smooth appearance. Pic attached of pre-mesh. The issue is present even at the rear of the SG with the grid lines emerging from the two points diverging non-parallel to each other.

I totally want to avoid this, and want to keep a smooth structured grid with rectangular cells to the maximum extent possible. Please help, I don't know which feature to use to obtain a proper grid. The proper grid from a similar case study is shown below.
Attached Images
File Type: png geometry.PNG (9.1 KB, 26 views)
File Type: jpg blocks_diverging pre-mesh.jpg (26.4 KB, 22 views)
File Type: jpg pre-mesh_coarse.jpg (41.4 KB, 21 views)
File Type: jpg fig_ideal mesh_nasa.jpg (86.3 KB, 31 views)
ramkr is offline   Reply With Quote

Old   June 12, 2022, 16:22
Default
  #2
Senior Member
 
Sebastian Engel
Join Date: Jun 2011
Location: Germany
Posts: 567
Rep Power: 21
bluebase will become famous soon enough
Use the Extend Splits feature.
Blocking > Split Block > Extend Splits, use All and apply.


Since you have split only a selected block, but not all (valid practice here), some edges are created implicitly to maintain a valid grid structure. With extend splits, you can unmask those edges. This action will allow you to regain the bunching control on the far field edges.




Add.: You might need to collapse a block on the (likely) upstream side. It seems there is a triangular, degenerated block.

Last edited by bluebase; June 12, 2022 at 16:24. Reason: Addtitum
bluebase is offline   Reply With Quote

Old   June 17, 2022, 02:56
Default
  #3
Member
 
Chrowale
Join Date: Sep 2021
Location: Bandung, Indonesia
Posts: 63
Rep Power: 5
mluckyw is on a distinguished road
I think it would be just to move the vertices in both downstream and upstream should do the trick, just move it in the z direction and eye ball it to be straight as possible (not recommended but it gets the job done).

Final thing is the collapse block in the upstream I think are necessary as bluebase mentioned.

Best regards
Lucky
mluckyw is offline   Reply With Quote

Old   July 10, 2022, 04:15
Default Structured multi-block mesh non-smooth
  #4
New Member
 
S Ram Kumar
Join Date: Jan 2019
Location: India
Posts: 12
Rep Power: 7
ramkr is on a distinguished road
Hello,
thanks to both, bluebase and lucky. I did give it a try once, but there seems to be atleast some level of such triangular blocks, owing to the two vertices that automatically get generated because of the shock generator. I have merged the two vertices into a single point by association. I hope this was what you had meant.

https://drive.google.com/file/d/1bAD...ew?usp=sharing
Attached Images
File Type: jpg extend split-1.jpg (26.6 KB, 15 views)
ramkr is offline   Reply With Quote

Reply

Tags
diverging grid lines, icem 18.1, meshing 2d, meshing algorithms, non-smooth transition


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
Block structured hexagonal mesh vs automated tetra mesh inside Workbench for CFD Chander CFX 3 November 27, 2011 17:24
[Commercial meshers] Icem Mesh to Foam jphandrigan OpenFOAM Meshing & Mesh Conversion 4 March 9, 2010 03:58
2d irregular grid Remy Main CFD Forum 1 December 22, 2008 05:49
How to control Minximum mesh space? hung FLUENT 7 April 18, 2005 10:38
unstructured vs. structured grids Frank Muldoon Main CFD Forum 1 January 5, 1999 11:09


All times are GMT -4. The time now is 10:28.