Creating and Editing Tetrahedron Meshes

• Select to mesh the 3D geometry with linear tetrahedron elements.
• Select to mesh the 3D geometry with quadratic tetrahedron elements.

To initialize the Size and Absolute sag values based on the overall support size, click Initialize from geometry.

1. In the Size box, enter a value for the element size.
2. To specify a maximum gap between the mesh and the geometry, enter a value for Absolute sag.

   
   
   

Boundary layer elements are stacked normal to solid walls. The elements are relatively thin in the stacking direction to provide a high mesh density in the direction normal to the fluid flow. This specialized mesh configuration is useful for capturing transition effects such as the significant velocity and temperature gradients that might occur near pipe walls and other structures due to viscous and heat transfer effects. The layers generally decrease in density as they get further from the boundary.

1. In the Type box, choose one of the following distributions:
   • Uniform to distribute elements uniformly.
   • Arithmetic to distribute elements using an arithmetic progression.
   • Geometric to distribute elements using a geometric progression.

2. Specify the Number of layers.
3. Specify the First layer thickness.

   The first layer is the layer closest to the boundary. Its thickness determines the density of the boundary layer.

4. Toggle off Only tet elements to generate boundary layers using primarily prismatic elements.

   Some pyramids and tetrahedrons might be used to mesh sharp corners and narrow sections.

The recommended approach in most cases is to use global boundary layers with excluded faces for inlets and outlets. Use Local Specifications to exclude faces from global boundary layer application or to use local boundary layers instead of global ones.

See Editing or Loading Tetrahedron Mesh Parameters.

1. Select Automatic mesh capture.
   The Apply on box is activated to let you select meshes to be captured.
2. Select the meshes to be captured either in the 3D area or in the tree.

   Tip: To select all meshes at once, right-click the Apply on field, and choose Select all.

3. Select the method of node capture for the captured faces.

   Option	Description
   Projection	Project the nodes of the source edge onto the target.
   Coincidence	Superimpose the nodes of the source edges and the target. The nodes are duplicated, not shared, with the source and target nodes in the same locations.
   Condensation	Merge the nodes of the source edges and the target. The nodes are shared and not duplicated.

4. In the Tolerance box, enter a maximum distance to capture nodes and edges of elements of the selected mesh parts.
5. To automatically project curves from nearby features, select Automatic curve capture.

   The curve projection tolerance is the same as the mesh capture tolerance specified for the automatic mesh capture.

The edge nodes of the captured mesh and the surface rule mesh are shared; they are not duplicated. The mesh capture is performed dynamically on all constraints (free edges, internal edges,...) and after all constraint modifications.

See Adding Local Mesh Specifications.

To change the display parameters applied when entering the Tetrahedron Mesher, click ... and choose one or more options.

• OK to save the parameters that you defined, to create the mesh, and to close the dialog box. To generate and visualize the mesh, you must update it.
• Mesh to save the parameters you defined and to create, update, and generate the mesh.

  The PLM Update progress bar appears. The mesh dialog box remains open to allow further edits.

• Cancel to cancel the modifications and to close the dialog box.