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

[Gmsh] Generating a parabolic profile in gmsh

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 12, 2012, 03:57
Default Generating a parabolic profile in gmsh
  #1
Member
 
Join Date: Feb 2012
Posts: 57
Rep Power: 14
matt.mech.eng is on a distinguished road
Hello,

I am trying to generate a parabolic profile (on the xy plane to be extruded along the z-direction) of a tank, to model the flow of fluid inside the tank with bubbleFoam. My issue is I have tried many ways to get such a geometry into openfoam.

My first try was to import an igs file with the geometry into gmsh, netgen or salome however none of these seemed to work..

I decided to generate the mesh from scratch, so I wrote a script to generate points along a parabola and join them all with straight lines (see attached image).
Then I try to generate a 2d surface mesh and I get the following error: "Error : Identical points in triangulation: increase element size or Mesh.RandomFactor"
and gmsh crashes.

How do I specify element size in gmsh? And what is Mesh.RandomFactor?

Cheers
Attached Images
File Type: jpg Screenshot.jpg (38.2 KB, 34 views)
File Type: jpg Screenshot-1.jpg (48.7 KB, 29 views)

Last edited by matt.mech.eng; March 12, 2012 at 04:48. Reason: pics uploaded
matt.mech.eng is offline   Reply With Quote

Old   March 12, 2012, 07:59
Default
  #2
New Member
 
GregorS's Avatar
 
Gregor Seljak
Join Date: Oct 2010
Posts: 21
Rep Power: 15
GregorS is on a distinguished road
From Gmsh documentation:
Mesh.RandomFactor
Random factor used in the 2D meshing algorithm (should be increased if RandomFactor * size(triangle)/size(model) approaches machine accuracy)
Default value: 1e-09

When generating mesh, position of every point is perturbated by small random value to avoid 3 aligned points. So for beginning you can set Mesh.RandomFactor=1e-7 (or something like that) in your .geo file and try again.
GregorS is offline   Reply With Quote

Old   February 21, 2016, 12:38
Default angle of element in gmsh
  #3
New Member
 
Goth ydamil
Join Date: Mar 2013
Posts: 13
Rep Power: 13
djamel is on a distinguished road
I want to change the angle of triangle element
djamel is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[swak4Foam] parabolic velocity profile with fluctuations (groovyBC?) newOFuser OpenFOAM Community Contributions 17 July 15, 2013 17:27
Half parabolic profile for the velocity inlet adele FLUENT 4 July 19, 2012 11:43
Doxygen documentation Tanay OpenFOAM Installation 9 September 23, 2011 11:40
[swak4Foam] Generating a parabolic Profile with groovyBC erklaerbaer OpenFOAM Community Contributions 9 June 6, 2010 14:51
[Gmsh] Import problem ARC OpenFOAM Meshing & Mesh Conversion 0 February 27, 2010 10:56


All times are GMT -4. The time now is 15:29.