Add unstructured and structured mesh files fort the Gmsh rectangular quadrilateral tutorial

Author: nikoscham

assets/gmsh_rect_quad.png

@@ -123,14 +123,14 @@ <h2 id="gmshfileimport"><a name="gmshfileimport"></a>Gmsh File Import</h2>
     printVersion();
 
     // Fetch the mesh file
-    const response = await fetch("./rect_quad.msh"); // .msh version 4.1 is currently supported
+    const response = await fetch("./rect_quad_unstruct.msh"); // .msh version 4.1 is currently supported
     if (!response.ok) {
       throw new Error(`Failed to load mesh file: ${response.status} ${response.statusText}`);
     }
     const meshContent = await response.text();
 
     // Create a File object with the actual content
-    const meshFile = new File([meshContent], "rect_quad.msh");
+    const meshFile = new File([meshContent], "rect_quad_unstruct.msh");
 
     // Create a new FEAScript model
     const model = new FEAScriptModel();
@@ -281,9 +281,9 @@ <h2 id="generatedmesh"><a name="generatedmesh"></a>Generated Mesh</h2>
 
     <div class="center-image">
       <img
-        src="../assets/gmsh_rect_quad.png"
+        src="../assets/gmsh_rect_quad_unstruct.png"
         alt="Quadrilateral mesh generated by Gmsh"
-        style="max-width: 80%; height: auto"
+        style="max-width: 40%; height: auto"
       />
       <p><em>Figure: Quadrilateral mesh generated using the rect.geo script with Gmsh</em></p>
     </div>
@@ -334,14 +334,14 @@ <h2 id="results"><a name="results"></a>Results</h2>
         printVersion();
 
         // Fetch the mesh file
-        const response = await fetch("./rect_quad.msh");
+        const response = await fetch("./rect_quad_unstruct.msh"); // .msh version 4.1 is currently supported
         if (!response.ok) {
           throw new Error(`Failed to load mesh file: ${response.status} ${response.statusText}`);
         }
         const meshContent = await response.text();
 
         // Create a File object with the actual content
-        const meshFile = new File([meshContent], "rect_quad.msh");
+        const meshFile = new File([meshContent], "rect_quad_unstruct.msh");
 
         // Create a new FEAScript model
         const gmshModel = new FEAScriptModel();
@@ -395,5 +395,8 @@ <h2 id="results"><a name="results"></a>Results</h2>
     </script>
 
     <p>&#169; 2023-<span id="currentYear"></span> FEAScript</p>
+    <script>
+      document.getElementById("currentYear").innerHTML = new Date().getFullYear();
+    </script>
   </body>
 </html>

assets/gmsh_rect_quad_struct.png

@@ -3,6 +3,8 @@
 // Use the command "gmsh rect.geo -2" to generate the mesh
 
 lc = 0.2; // Characteristic length (mesh density)
+// Note: In the structured case, the lc = 0.2 no longer directly determines the mesh size,
+// as the Transfinite Curve commands explicitly set the number of elements along each boundary
 
 // Points (x, y, z, mesh size)
 Point(1) = {0, 0, 0, lc};     // Bottom left
@@ -29,7 +31,15 @@ Physical Line("left")   = {4};
 // Physical Surface (optional, for FEM domains)
 Physical Surface("domain") = {1};
 
+// Create structured mesh
+//Transfinite Curve{1} = 20;
+//Transfinite Curve{2} = 10;
+//Transfinite Curve{3} = 20;
+//Transfinite Curve{4} = 10;
+//Transfinite Surface{1};
+
 // Generate 2D mesh
 Recombine Surface{1}; // Turns triangle mesh into quads
+Mesh.ElementOrder = 2; // Set quadratic elements 
 Mesh 2;