CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLUENT

doubt on meshing a cylinder

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 22, 2005, 12:55
Default doubt on meshing a cylinder
  #1
FELIX JOE S
Guest
 
Posts: n/a
Sir,

I am a student learning fluent in IIT Chennai. I had a problem in meshing a cylinder of 0.004m(outer diameter) and 0.0037m(inner diameter) [i.e. thickness of 0.0003m ] and a height of 0.02m height. So the problem is that the meshing error(in the Gambit) is occuring .I used all the three basic volume meshes. The error is that " SIGSEGV (segmentation violaton) error" . All occurs for the mesh size of 0.0001 . please suggest me ways to solve it.

thanking you

JOE
  Reply With Quote

Old   July 22, 2005, 13:06
Default EXPLAIN ME ABOUT AN ERROR
  #2
MANIVANNAN
Guest
 
Posts: n/a
Sir,

I am a student learning fluent in IIT Chennai. I had a problem in axis symmetric valve the problem is in fluent which says divergence detected in AMG solver: X momentum the inlet we give as total gauge pressure & outlet is pressure which is 0.

please suggest me ways to solve it.

thanking you
  Reply With Quote

Old   July 22, 2005, 13:31
Default Re: EXPLAIN ME ABOUT AN ERROR
  #3
AJG
Guest
 
Posts: n/a
I think u are using to many nodes! the density is to high for your server. Try a more coarse mesh.
  Reply With Quote

Old   July 23, 2005, 00:31
Default Re: doubt on meshing a cylinder
  #4
Mahesh
Guest
 
Posts: n/a
create a cylindet of 4 & 3.7 as dimensions. in Fluent, say grid is created in mm. So it will take new dimensions as 0.004 & 0.0037
  Reply With Quote

Old   July 23, 2005, 02:21
Default Re: doubt on meshing a cylinder
  #5
Mehdi Ghoddosy
Guest
 
Posts: n/a
Dear Felix:

What meshing scheme are you using? I think using Map scheme can help you. However if you decet you meshing scheme i can give you more offers.

Best Regards
  Reply With Quote

Old   July 23, 2005, 05:15
Default Re: EXPLAIN ME ABOUT AN ERROR
  #6
Swarup
Guest
 
Posts: n/a
Check your problem set-up, especially your boundary condition values. I hope you understand what is meant by divergence. your variable values are going out of bounds. Are you getting some messages before divergence detection message is thrown? Swarup.
  Reply With Quote

Old   July 23, 2005, 11:47
Default Re: doubt on meshing a cylinder
  #7
sharuk
Guest
 
Posts: n/a
use size function
  Reply With Quote

Old   July 25, 2005, 07:36
Default Re:Re: doubt on meshing a cylinder
  #8
FELIX JOE S
Guest
 
Posts: n/a
Sir

I have tried it doing that also but the error is in the mesh of that length to thickness ratio (as i think). The mesh scheme i used predominently was TET/HYBRID still i also used Hex Map. I also modeled it in mm still the same error is present.I still need the mesh size for both i.e. (1) if i model it in same size (2) if in scaled one but i have tried both of it. I still need more advice

Thank you for your valued suggestions

JOE

  Reply With Quote

Old   July 25, 2005, 07:45
Default Re:Re: doubt on meshing a cylinder
  #9
FELIX JOE S
Guest
 
Posts: n/a
Sir

I have tried it doing that also but the error is in the mesh of that length to thickness ratio (as i think). The mesh scheme i used predominently was TET/HYBRID still i also used Hex Map. I also modeled it in mm still the same error is present.I still need the mesh size for both i.e. (1) if i model it in same size (2) if in scaled one but i have tried both of it. I still need more advice

Thank you for your valued suggestions

JOE

  Reply With Quote

Old   July 25, 2005, 08:04
Default Re: doubt on meshing a cylinder
  #10
Mehdi Ghoddosy
Guest
 
Posts: n/a
Dear Felix:

I think your mesh and model sizes does not have any problem, and range in conventional geometries. Also, meshing cylenders is a conventional and frequently used case in CFD problems. So, the problem arises in creating geometry or meshing process. To avoid this, first forget your cylinder thickness and try to mesh remaining geometry. Fisrt, grade start and end caps(circles). Split them to four curves and try to mesh the cap surface using Map scheme. Then, grade the cylinder wall, and mesh it using Map scheme. Now, mesh the volume using Map or Cooper scheme. Following this concept no problem should be arised. If you got the error again, there is an error in your program, or concept of defining mesh or geometry. If no problem arised we would discuss about ramainnig part of your model. Good luck.

Best Regards

Mehdi Ghoddosy

  Reply With Quote

Old   July 25, 2005, 08:08
Default Re: doubt on meshing a cylinder
  #11
Mehdi Ghoddosy
Guest
 
Posts: n/a
Dear Felix:

Excuse me, forgot to say, create the geometry using down-top approach. Means that first create the circles and then wall surface, then compose the volume using these faces.
  Reply With Quote

Old   July 26, 2005, 03:44
Default Re: EXPLAIN ME ABOUT AN ERROR
  #12
sharuk
Guest
 
Posts: n/a
this is for manivannan, check ur boundary conditions, and reduce the relaxation factors.if it doesn't work go for coupled/implicit solver.i'm in krishna hostel, room no 111, no. 9884204548, tell me if u got it correct. sharuk
  Reply With Quote

Old   July 27, 2005, 04:06
Default Re:Re: doubt on meshing a cylinder
  #13
zxaar
Guest
 
Posts: n/a
why don't you try making mesh in mm and then scale it in fluent. if the problem coming from mesh dimensions. otherwise sigmentation violation suggest that there is a problem with your geomtery. check that.
  Reply With Quote

Old   July 27, 2005, 08:06
Default Re:Re: doubt on meshing a cylinder
  #14
Mehdi Ghoddosy
Guest
 
Posts: n/a
Dear Felix:

Excuse me, if I have not read your message carefully; but as I remember you said that tried to generate the mesh with dimension in mm and got the error again. However, if you have not tried to generate your mesh in mm, I recommend try it first.

Regards Mehdi Ghoddosy
  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
2D planar cylinder meshing problem saisanthoshm88 ANSYS Meshing & Geometry 15 December 27, 2010 12:14
[ICEM] (ICEM CFD) meshing over a cylinder vmlxb6 ANSYS Meshing & Geometry 6 August 11, 2010 14:37
Meshing inside a cylinder so that the edges contain more cells than the center Bertrand OpenFOAM Native Meshers: blockMesh 1 April 13, 2010 04:46
Best Meshing scheme for Cylinder Nutrex Main CFD Forum 4 July 29, 2008 11:03
doubt on meshing joe FLUENT 2 September 12, 2005 13:17


All times are GMT -4. The time now is 17:30.