CFD Online URL
[Sponsors]
Home > Forums > ANSYS Meshing & Geometry

[Other] Ansys meshing airfoil and / or compressor blades

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

Like Tree1Likes
  • 1 Post By baw192

Reply
 
LinkBack Thread Tools Display Modes
Old   August 30, 2010, 09:34
Default Ansys meshing airfoil and / or compressor blades
  #1
New Member
 
Markus Siebenhaar
Join Date: Aug 2010
Posts: 1
Rep Power: 0
baw192 is on a distinguished road
Hi,

First of all let me say that I saw there are a lot of questions concerning airfoil meshing and I did read a lot of them for the last few weeks. If this question has been answered before and I missed it I am very sorry and would be happy if somebody can give me a link to the thread.

I am a student of aeronautics and currently work on a project on which I have to simulate the flow around 2D airfoils which I generate using javafoil, then import into DesignModeller and mesh the farfield with the mesher provided in the Ansys 12.1 workbench. I am working on this now for several weeks but do not seem to find a good solution. I looked at a lot of tutorials but they are either for Gambit which is no longer in use basically since the day I started or ICEM.

I created the farfield and the airfoil geometry in DesignModeler simular to the one used in this tutorial.
http://courses.cit.cornell.edu/fluent/airfoil/step1.htm

I used mapped meshing and tried to resolve the boundary layer as best as I could. However I is never satisfying. Any refinement of the mesh beyond the point where I am now results in an error. I used the y+ calculator to estimate the size of the first cell which come out to be 0.0000056m. But I cannot enter a length even close to that.
The y+ values stayed around 40 to 100. The only way I could bring them down was to use the refine mesh function in Fluent. Which resulted in a mesh with around 200.000 elements and a very high aspect ratio.

In the next step I want to use the same airfoil, but stack them on top of each other to simulate a grid of compressor blades. for that I want to use an O-grid around the airfoil which doesn't seem to be working very well either, I susbect it has something to do with the sharp trailing edge on the airfoil. But this problem is secondary.

Any help is appreciated. Thank you very much in advance.

Is Ansys mesher capable of this type of meshing or should I tell my Proffessor that it is way easier and worth it to get ICEM instead?

Thank you very much.
Regards
Markus
Attached Images
File Type: jpg Mesh NACA0012 wide.jpg (96.5 KB, 131 views)
File Type: jpg Mesh NACA0012 detail.jpg (94.1 KB, 109 views)
File Type: jpg Mesh NACA0012 close.jpg (97.9 KB, 116 views)
KKPradeep likes this.

Last edited by baw192; August 31, 2010 at 04:43. Reason: adding pictures / mesh file to big
baw192 is offline   Reply With Quote

Old   January 1, 2011, 11:38
Default how did you get a C grid?
  #2
New Member
 
Akash
Join Date: Nov 2010
Location: Southampton
Posts: 3
Rep Power: 6
akash_morar is on a distinguished road
Would just like to know how you got a C grid like that in the ansys default mesher, i've been trying for a while but havent succeeded. I've been creating and importing in curve files into the design modeller, making the the outer c grid shape and then meshing it with loads of different settings. What settings did you use?
akash_morar is offline   Reply With Quote

Old   January 2, 2011, 17:31
Default ICEM CFD to get the job done.
  #3
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,660
Blog Entries: 1
Rep Power: 34
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
Yes, eventually ANSYS Meshing will be able to handle this, but not at the current release. I would suggest installing ICEM CFD to get the job done.

You can follow the ICEM CFD instructions at

http://www.youtube.com/user/ansysinc#p/u/8/tYrbScUH9RE

This is the first Video of three... If it doesn't immediately offer you the rest when it is over, you can find them here...

http://www.youtube.com/user/ansysinc

Best regards,

Simon
PSYMN is offline   Reply With Quote

Old   January 2, 2011, 21:38
Default
  #4
jsm
Senior Member
 
JSM
Join Date: Mar 2009
Location: India
Posts: 143
Rep Power: 10
jsm is on a distinguished road
Hi Markus,

One more suggestion. Convert your model to millimeter unit from meter. So you can avoid numbers with more digits after decimal point (like 0.0000056m --> 0.0056mm)

with regards,
JSM
__________________
With regards,
JSM
jsm is offline   Reply With Quote

Old   April 1, 2011, 06:10
Default problem with boundary settings in ICEM
  #5
New Member
 
jim
Join Date: Apr 2011
Posts: 1
Rep Power: 0
jimbob is on a distinguished road
Hi all,

I have followed the youtube tutorials for creating a mesh around a 2D airfoil with ICEM, rather successfully. However when I run my simulation in fluent, my y+ values are not correct (around 20-40). Like Markus I have used an online calculator to establish that the size of my first cell (starting from the airfoil) must be 8.3x10^-6 m (in order to get y+ roughly equal to 1). I have no idea how to do this with ICEM (being new to CFD), could you please help?
Thank you very much,

Best Regards

Jim
jimbob is offline   Reply With Quote

Old   April 2, 2011, 10:58
Default Edge Params
  #6
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,660
Blog Entries: 1
Rep Power: 34
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
Under Blocking tab => Premesh Params => Edge Params, you will find options to sent the end spacing of the radial Ogrid edges...

Just set the Spacing1 or Spacing2 (which ever is correct) to the 8.3x10^-6 m size that you wanted for your y+ = 1.

Don't forget to also turn on "copy parameters" "To All Parallel Edges"
__________________
-----------------------------------------
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   August 24, 2011, 08:15
Default
  #7
New Member
 
Gon
Join Date: Aug 2011
Posts: 3
Rep Power: 5
gontxo is on a distinguished road
Quote:
Originally Posted by jimbob View Post
Hi all,
Like Markus I have used an online calculator to establish that the size of my first cell (starting from the airfoil) must be 8.3x10^-6 m (in order to get y+ roughly equal to 1).
Hello,

Could you please post the link to that calculator?

thank you in advance!!
gontxo is offline   Reply With Quote

Old   August 24, 2011, 08:31
Default
  #8
Administrator
 
pete's Avatar
 
Peter Jones
Join Date: Jan 2009
Posts: 637
Rep Power: 10
pete is on a distinguished road
http://www.cfd-online.com/Links/tools.html#yplus
pete is offline   Reply With Quote

Old   September 23, 2011, 01:43
Default
  #9
New Member
 
Pradeep
Join Date: Aug 2011
Posts: 2
Rep Power: 0
KKPradeep is on a distinguished road
Hello Markus,
Can you please send me the replay file. I am getting error while doing the 3rd part of the video file.
please mail me at karrikumar@gmail.com

regards, Pradeep
KKPradeep 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



All times are GMT -4. The time now is 05:48.