[CFD-Lover]

Hey All,

I have been reading and practising how to create a 3D mesh in gmsh. I have come to a question I was not able to answer. Anyway, I created two line with following coordinates;

Point(1) = {2.5, 0, 0, 0.0};
Point(2) = {5.25, 0, 0, 0.0};
Point(3) = {8, 0, 0, 0.0};

Then I extruded the same points 14 in the z direction using the following points;

Point(4) = {2.5, 0, 14, 0.0};
Point(5) = {5.25, 0, 14, 0.0};
Point(6) = {8, 0, 14, 0.0};

Now, I have two rectangles with tow Plane surfaces as shown below;

pic1.jpg

I created a grid for the two rectangles as shown below using transfinite surface algorithm;

Transfinite Line {5, 2, 4, 1} = 20 Using Progression 1;
Transfinite Line {6, 7, 3} = 100 Using Progression 1
Transfinite Surface "*";
Recombine Surface "*";

pic2.jpg

Now that we have a 2d mesh, I thought that it is easy to rotate four times to obtain the full 3d for the cylinder as shown below;

pic3.jpg
pic4.jpg
pic5.jpg

All I want to do is maintaining the same 2d mesh size that I created using transfinite to be set in all 3d domain. To do so, when I applied extrude the 2d surface, I used the command layer{30};, which it totally do not know what it does as follows;

Extrude {{0, 0, 1}, {0, 0, 0}, Pi/2} {
Surface{9, 11}; Layers{30};
}
Extrude {{0, 0, 1}, {0, 0, 0}, Pi/2} {
Surface{33, 55}; Layers{30};
}
Extrude {{0, 0, 1}, {0, 0, 0}, Pi/2} {
Surface{99, 77}; Layers{30};
}
Extrude {{0, 0, 1}, {0, 0, 0}, Pi/2} {
Surface{121, 143}; Layers{30};
}

Applying extrude command and Layer{30} has created a mesh that look reasonable, but it did not match the mesh size of the two rectangles that I created earlier. Can somebody explain how the command layer works and how can I create it with the same size of the 2d before extrusion?

Thank you in advance,