CFD Online Logo CFD Online URL
Home > Forums > ANSYS Meshing & Geometry

ICEM aircraft mesh trailing edge difficulty

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

Like Tree2Likes
  • 1 Post By MontyR
  • 1 Post By PSYMN

LinkBack Thread Tools Display Modes
Old   July 18, 2011, 11:37
Default ICEM aircraft mesh trailing edge difficulty
New Member
Monty Roberts
Join Date: Jul 2011
Posts: 4
Rep Power: 8
MontyR is on a distinguished road
I am having a problem with meshing trailing edges. I have tried to associate the mesh with the edge curves. This does not seem to work.

The trailing edge of the root fillet is also a problem.

I'm a newb so feel free to point out any obvious problems, they are probably not obvious to me....

Any tips?
Attached Images
File Type: jpg DF1.jpg (101.3 KB, 133 views)
File Type: jpg DF2.jpg (91.2 KB, 110 views)
File Type: jpg RootFillet.JPG (73.6 KB, 104 views)
MontyR is offline   Reply With Quote

Old   July 20, 2011, 11:16
New Member
Monty Roberts
Join Date: Jul 2011
Posts: 4
Rep Power: 8
MontyR is on a distinguished road
I have improved the trailing edge situation. Mainly by changing the Edge Criterion in Volume Meshing Parameters under the Global Meshing Setup tab.

I also tried using define thin cuts. However, this resulted in a lot of holes in the mesh along the leading edge.

There are other vexing problems now:
Attached Images
File Type: jpg DF3.jpg (65.5 KB, 83 views)
File Type: jpg DF4.jpg (82.0 KB, 76 views)
File Type: jpg DF5.JPG (63.5 KB, 77 views)
MontyR is offline   Reply With Quote

Old   July 22, 2011, 14:39
Default Improvment
New Member
Monty Roberts
Join Date: Jul 2011
Posts: 4
Rep Power: 8
MontyR is on a distinguished road
After a lot of head scratching, I seem to be getting somewhere.

For those who come here searching for answers in the future I thought I would share what I learned.

1.) Trying to fix a problem like this by lowering the edge criterion will reach a point of diminishing returns. It is far better to construct the geometry so that the mesher "likes" it. I did this by truncating the aft edge of the airfoils. There is a blunt trailing edge about .25 in thick. This allows you to force the mesh to a smaller size along the trailing edge and prevents the small angle problem.

2.) Using thin cuts is also not a very good option.

This is starting to look like something I feel like I can run an analysis on. I still need to increase the fluid mesh density around the nose of the aircraft.......First I need to buy some more RAM
Attached Images
File Type: jpg CFD6.jpg (100.8 KB, 102 views)
Prakash.Paudel likes this.
MontyR is offline   Reply With Quote

Old   July 23, 2011, 13:56
Retired from CFD Online
PSYMN's Avatar
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,665
Blog Entries: 1
Rep Power: 39
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
I admire your persistence to try and figure this out. It looks like you were getting close on your own, but like Wile-E-Coyote, it may have been good to combine methods in the right way...

Edge criterion definitely matters, but it may not get you all the way there on its own...

You should also use thin cuts, but they will fail if your trailing edge is not in a different component... So if the top surface is "A" and the bottom is "B", the curve between them can not be in "A" or "B", Put the curve in "C". In fact, if those two parts touch anywhere in the model, the thin cut will fail and you will see a message about it scroll by in the message window. This has to do with the logic of the thin cut algorithm and you can read more about it in the help.

Instead of creating a small flat edge to put a size on, you can just apply a finer size to the trailing edge curve its self...

You could also create a density line by picking points along the trailing edge... (this can be used to set the max size in this critical area).
Prakash.Paudel likes this.
Please help guide development at ANSYS by filling in these surveys

Public ANSYS ICEM CFD Users Survey

This second one is more general (Gambit, TGrid and ANSYS Meshing users welcome)...

CFD Online Users Survey
PSYMN is offline   Reply With Quote

Old   July 23, 2011, 21:46
New Member
Monty Roberts
Join Date: Jul 2011
Posts: 4
Rep Power: 8
MontyR is on a distinguished road

Thanks for the tips. I will try the edge curve trick. I could not get it to work because (as you accurately surmised)...I had it in the same part.

I was being lazy by modeling the surfaces that way, the flat trailing edge is more accurate.

I have done some structural analysis, but not much CFD...I'm learning as I go. Thin edges and points where geometry all comes together are my long term the modeling world, as well.

Unfortunately, I had everything ready to load into fluent, only to discover that our license only supports 500K cells...I have closer to 5 million, before refinement and using symmetry. Our license also does not support parallel processing.

This isn't commercial, and is only me trying to learn the ropes while working on an interesting problem.

Seems I'll be looking into OpenFoam......
MontyR is offline   Reply With Quote


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
[ICEM] Hexa mesh, curve mesh setup, bunching law Anorky ANSYS Meshing & Geometry 4 November 12, 2014 01:27
fine mesh in wake trailing edge jose antonio ANSYS Meshing & Geometry 1 August 11, 2011 19:10
ICEM Tetra mesh, Size reduction and Skewness problem Catthan ANSYS Meshing & Geometry 6 December 5, 2010 20:39
Actuator disk model audrich FLUENT 0 September 21, 2009 07:06
Mesh from ICEM CFD to CFX ! Error ! Why ? Thanks ! Vu Trinh Tuan CFX 11 March 28, 2005 19:04

All times are GMT -4. The time now is 11:34.