Use Mesh control faces for precise control of the mesh in specific regions of the geometry, without affecting the geometry used for assigning physics.

To fully resolve the gradients in a field in certain regions of a domain, a finer mesh may be required. To reduce the memory required to solve the model, a swept mesh can sometimes be used. For geometries where it is not possible to sweep a mesh in the entire domain, partition the domain, then sweep the mesh in the domain created by the partitioning, as shown in Figure 7-42. By designating the created face as a mesh control face, it will only be visible in mesh mode, and only before the mesh is generated. As soon as the mesh is built inside the domains adjacent to the face, the face itself and the edges adjacent to the mesh control face are removed.

The operation removes the selected faces that are isolated or are located between two domains by ignoring them and composing the adjacent domains as shown in Figure 7-42 and Figure 7-43. The faces become available when you build the mesh. This makes it possible to partition a domain to prepare it for swept meshing, or to control the mesh size in a specific region, without modifying the geometry that appears when assigning physics settings.

An advantage of working with mesh control faces is that when the faces have been removed, the mesher can move mesh vertices to make a smoother the size transition across the removed entities (see Figure 7-43). This behavior is controlled by the settings in the section Control Entities of the mesh operation used to mesh the domains.

To use the operation, in the Geometry toolbar, from the Virtual Operations menu (), select Mesh Control Faces (). Then enter the properties of the operation using the following sections:

Select the faces that you want to use for mesh control in the Graphics window. They then appear in the Face to include list. If the geometry sequence includes user-defined selections above the Mesh Control Faces node, choose Manual to select faces, or choose one of the selection nodes from the list next to Faces to include.

Click the Active button to toggle between turning ON and OFF the Faces to include selections.

Use the Include adjacent vertices and edges check box to specify if the operation also includes the ignorable vertices and edges adjacent to of the faces.