[algc]

Hi all,

I'm using gmsh for the first time, and trying to create a mesh around a cylinder for use in OpenFOAM. When I try to extrude the mesh into 3D using the translation, it crashes immediately and gives a segmentation fault. My .geo file is below:
__________________________________________
// Gmsh project created on Sat Sep 24 15:53:50 2022
SetFactory("OpenCASCADE");
//+

xbox = -1;
ybox = 1;
xfar= 20;
xinlet = -8;
yfar = 8;
ncyl = 200;
ninlet= 32;
ntop = 32;
nbot = 32;
nybox = 16;
nxbox = 128;
noutlet = 32;

Circle(1) = {0, 0, 0, 0.5, 0, 2*Pi};
//+
Point(2) = {xbox, ybox, 0, 1.0};
//+
Point(3) = {xbox, -ybox, 0, 1.0};
//+
Point(4) = {xfar, -ybox, 0, 1.0};
//+
Point(5) = {xfar, ybox, 0, 1.0};
//+
Point(6) = {xinlet, yfar, 0, 1.0};
//+
Point(7) = {xinlet, -yfar, 0, 1.0};
//+
Point(8) = {xfar, -yfar, 0, 1.0};
//+
Point(9) = {xfar, yfar, 0, 1.0};
//+
Line(2) = {6, 9};
//+
Line(3) = {6, 7};
//+
Line(4) = {7, 8};
//+
Line(5) = {8, 4};
//+
Line(6) = {9, 5};
//+
Line(7) = {4, 5};
//+
Line(8) = {2, 5};
//+
Line(9) = {3, 4};
//+
Line(10) = {2, 3};
//+
Transfinite Curve {1} = ncyl Using Progression 1;
//+
Transfinite Curve {3} = ninlet Using Progression 1;

//+
Transfinite Curve {2} = ntop Using Progression 1;
//+
Transfinite Curve {4} = nbot Using Progression 1;
//+
Transfinite Curve {10} = nybox Using Progression 1;
//+
Transfinite Curve {7} = nybox Using Progression 1;
//+
Transfinite Curve {8} = nxbox Using Progression 1;
//+
Transfinite Curve {9} = nxbox Using Progression 1;
//+
Transfinite Curve {6} = noutlet/2 Using Progression 1;
//+
Transfinite Curve {5} = noutlet/2 Using Progression 1;
//+
Curve Loop(1) = {3, 4, 5, -9, -10, 8, -6, -2};
//+
Plane Surface(1) = {1};
//+
Curve Loop(2) = {8, -7, -9, -10};
//+
Curve Loop(3) = {1};
//+
Plane Surface(2) = {2, 3};

___________________________________

Any help will be greatly appreciated!

[aerosayan]

I played around a little bit, and did get a 3d grid, but the error report says something definitely isn't correct. Need to find out more about how to correct the errors.

I did it with the GUI, but the script had this code added automatically to the end of it. Maybe you can also add it to your script, and try it.

//+
Extrude {0, 0, 10} {
  Surface{1}; Layers{10}; Recombine;
}

[aerosayan]

The 2 sections don't combine. Don't know why. Additional code:

//+
Extrude {0, 0, 5} {
  Surface{1}; Surface{2}; Layers{5}; Recombine;
}

[aerosayan]

Okay, now it works.

• Open in GMSH.
• Click on Mesh->3D.

Full script:

// Gmsh project created on Sat Sep 24 15:53:50 2022
SetFactory("OpenCASCADE");
//+

xbox = -1;
ybox = 1;
xfar= 20;
xinlet = -8;
yfar = 8;
ncyl = 200;
ninlet= 32;
ntop = 32;
nbot = 32;
nybox = 16;
nxbox = 128;
noutlet = 32;

Circle(1) = {0, 0, 0, 0.5, 0, 2*Pi};
//+
Point(2) = {xbox, ybox, 0, 1.0};
//+
Point(3) = {xbox, -ybox, 0, 1.0};
//+
Point(4) = {xfar, -ybox, 0, 1.0};
//+
Point(5) = {xfar, ybox, 0, 1.0};
//+
Point(6) = {xinlet, yfar, 0, 1.0};
//+
Point(7) = {xinlet, -yfar, 0, 1.0};
//+
Point(8) = {xfar, -yfar, 0, 1.0};
//+
Point(9) = {xfar, yfar, 0, 1.0};
//+
Line(2) = {6, 9};
//+
Line(3) = {6, 7};
//+
Line(4) = {7, 8};
//+
Line(5) = {8, 4};
//+
Line(6) = {9, 5};
//+
Line(7) = {4, 5};
//+
Line(8) = {2, 5};
//+
Line(9) = {3, 4};
//+
Line(10) = {2, 3};
//+
Transfinite Curve {1} = ncyl Using Progression 1;
//+
Transfinite Curve {3} = ninlet Using Progression 1;

//+
Transfinite Curve {2} = ntop Using Progression 1;
//+
Transfinite Curve {4} = nbot Using Progression 1;
//+
Transfinite Curve {10} = nybox Using Progression 1;
//+
Transfinite Curve {7} = nybox Using Progression 1;
//+
Transfinite Curve {8} = nxbox Using Progression 1;
//+
Transfinite Curve {9} = nxbox Using Progression 1;
//+
Transfinite Curve {6} = noutlet/2 Using Progression 1;
//+
Transfinite Curve {5} = noutlet/2 Using Progression 1;
//+
Curve Loop(1) = {3, 4, 5, -9, -10, 8, -6, -2};
//+
Plane Surface(1) = {1};
//+
Curve Loop(2) = {8, -7, -9, -10};
//+
Curve Loop(3) = {1};
//+
Plane Surface(2) = {2, 3};
//+
Extrude {0, 0, 5} {
  Surface{1}; Surface{2}; Layers{5}; Recombine;
}

[algc]

Thank you so much! I'm going to bed now, will write more tomorrow.