Simple 2D Gmsh shock tube model

shock_tube.geo

// Gmsh project created on Mon Jun 17, 2024
SetFactory("OpenCASCADE");

// Define points
L = 0.5;    // Tube length
H = 0.05;   // Tube width
N = 10;     // Number of rectangles along length of the tube
Point(1) = {0, 0, 0, 1.0};
Point(2) = {L, 0, 0, 1.0};
Point(3) = {L, H, 0, 1.0};
Point(4) = {0, H, 0, 1.0};

// Connect points with lines to form the rectangle
Line(1) = {1, 2};
Line(2) = {2, 3};
Line(3) = {3, 4};
Line(4) = {4, 1};

// Define the rectangle as a surface
Line Loop(5) = {1, 2, 3, 4};
Plane Surface(6) = {5};

// Define transfinite lines with a specific number of nodes
Transfinite Line {1,3} = N+1; // Adjust number for refinement in length of the tube
Transfinite Line {2,4} = 1;   // Adjust number for refinement in the width of the tube

// Define transfinite surface using the specified lines
Transfinite Surface {6} = {1,2,3,4};

// Recombine the surface mesh into quadrilaterals
Recombine Surface {6};

// Set the mesh element size
Mesh.CharacteristicLengthMax = 0.1;

// Generate the 2D mesh
Mesh 2;

// Save the mesh to a file
Save "shock_tube.msh";