[Gmsh] Joining two pipes

Martin Vymazal martin.vymazal at vki.ac.be
Wed Aug 4 20:06:55 CEST 2010


  I would like to ask if anyone has an idea how (if at all) to join  
two cylindrical surfaces in gmsh. I have an 'msh' file after  
conversion from CAD data. The file contains 2 pipes which have the  
same axis but slightly different diameters, one following after the  
other. There's a small gap between the end of the first pipe and the  
beginning of the second pipe that I'd like to cover with a surface  
mesh, thus joining the two pipes.
  I have a circle (elementary entity number 1), which is the 'outlet  
ring' of the first pipe and another circle (elementary entity # 2) -  
'inlet ring' of the second pipe. Moreover, there's a line number 3  
joining one point of the first circle with another point on the second  
circle. These three lines form sort of a 'conical outline' - I have 2  
bases with slightly different radiuses and one surface line connecting  
them. I thought I could write this in my geo file (after merging the  
mesh with the two pipes):

   l1 = newreg;
   Line Loop(l1) = {1,2,3};
   Ruled Surface(newreg) = {l1};

Unfortunately, gmsh meshes only the surface defined by circle 1,  
instead of meshing the conical surface that I tried to define.

Could you please tell if what I'm trying to do is feasible? If so, do  
you have an idea how to do it?

Best regards,

    Martin Vymazal

This message was sent using IMP, the Internet Messaging Program.