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

[ICEM] High Skewness

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 22, 2013, 14:04
Default High Skewness
  #1
Senior Member
 
mohamed khedr emam
Join Date: Oct 2011
Location: Egypt
Posts: 121
Rep Power: 15
m5edr is on a distinguished road
Dear experts,
My Geometry (old case () is a single blade inside a big 120o enclosure sector , after long period i'm stuck with T-Grid skewness problem around the blade surface which appear strongly in Fleunt (after send my file from ICEM). The ICEM T-Grid skewness is high but quality and skewness are good.
I'm using Tetra, unstructured and Robust (octree) meshing techniques, I need a recommended ways to improve T-Grid skewness in ICEM (not Fluent).
Note: I noted that if the total height of blade prism is large, T-Grid skewness will be good but unfortunately in my case the first layer is very small (4e-5) due to y+ condition
image1: prsim
image2: High T.Grid Skewness elements on blade

Thanks in advance
Attached Images
File Type: jpg 22-Jun-13 7-00-06 PM.jpg (74.0 KB, 86 views)
File Type: jpg 22-Jun-13 7-01-20 PM.jpg (56.1 KB, 89 views)
m5edr is offline   Reply With Quote

Old   June 22, 2013, 17:11
Default
  #2
Far
Senior Member
 
Sijal
Join Date: Mar 2009
Location: Islamabad
Posts: 4,558
Blog Entries: 6
Rep Power: 54
Far has a spectacular aura aboutFar has a spectacular aura about
Send a message via Skype™ to Far
Where this problem occurs?
Far is offline   Reply With Quote

Old   June 22, 2013, 17:31
Default
  #3
Senior Member
 
mohamed khedr emam
Join Date: Oct 2011
Location: Egypt
Posts: 121
Rep Power: 15
m5edr is on a distinguished road
Hi Far
Quote:
Originally Posted by Far View Post
Where this problem occurs?
At blade surface seems to be between prism and blade surface mesh , here is the file http://www.4shared.com/rar/eJGwRtle/email.html
m5edr is offline   Reply With Quote

Old   June 23, 2013, 23:30
Default
  #4
Senior Member
 
mohamed khedr emam
Join Date: Oct 2011
Location: Egypt
Posts: 121
Rep Power: 15
m5edr is on a distinguished road
Any recommendation please
m5edr is offline   Reply With Quote

Old   June 24, 2013, 20:45
Default
  #5
Far
Senior Member
 
Sijal
Join Date: Mar 2009
Location: Islamabad
Posts: 4,558
Blog Entries: 6
Rep Power: 54
Far has a spectacular aura aboutFar has a spectacular aura about
Send a message via Skype™ to Far
reduce sizes on wing
Far is offline   Reply With Quote

Old   June 28, 2013, 04:01
Default Dealing with sharp trailing edge
  #6
Member
 
sadjad.s's Avatar
 
sadjad
Join Date: Jan 2012
Posts: 72
Rep Power: 14
sadjad.s is on a distinguished road
Send a message via Yahoo to sadjad.s
Hi mate,
I suggest make these changes in order to have higher quality mesh:
First as seen in the picture, shell mesh quality is of low quality. As said, garbage in, garbage out. Try improve quality higher than 0.5 by splitting and recreating cells at those areas.
Then run delaunay to have volume mesh.
I ran these two steps and my delaunay mesh quality was more than 0.4.
Next step is to grow prism. Prism meshing is somehow try and error process.
Try these methods:
Make max prism angle 180,
active/inactive Auto Reduction (in Advanced Prism Options)
try floating height by not setting initial height and total height.

The candidate area of bad quality prism is sharp side of airfoil. Try filleting that area with CAD software.

You can try Mulitizone Blocking, which would give high quality quad shell mesh in all of surfaces but one. (Blade Tip)

Beside these, you may have higher prism quality with TGrid, but because of periodic boundaries (i think) you can not export your mesh to TGrid.
Attached Images
File Type: jpg p1.jpg (39.9 KB, 60 views)
sadjad.s is offline   Reply With Quote

Reply


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
Removing cells with high skewness Parag Gadgil FLUENT 0 July 11, 2011 02:52
TGrid High Skewness khimkhim ANSYS Meshing & Geometry 1 February 18, 2010 00:36
Severe nonorthogonality and severe skewness problem qtian OpenFOAM Running, Solving & CFD 2 January 22, 2008 19:47
Interface between meshes and high skewness Danny FLUENT 0 September 13, 2005 12:23
Multicomponent fluid Andrea CFX 2 October 11, 2004 06:12


All times are GMT -4. The time now is 10:47.