Corner Refinement
Use the Corner Refinement () attribute to decrease the element size at sharp corners, as shown to the right in Figure 8-44. The node considers a vertex in 2D or an edge in 3D to be a sharp corner if the angle between the adjacent selected boundaries, with respect to the selected domain, is greater than a specified angle.
Figure 8-44: The default tetrahedral mesh for this backstep geometry (left). The image to the right shows how the tetrahedral mesh is refined close to the sharp corner when a Corner Refinement node has been added.
To add a Corner Refinement () node, select boundaries in the graphics, then choose one of the following:
Right-click a mesh operation and choose Corner Refinement () to add it as a local attribute.
To add it as a global node in the meshing sequence:
In The Mesh Toolbar, choose Corner Refinement from the Sizing () menu.
Right-click the Mesh node and choose Corner Refinement ().
Then enter the properties using the following sections:
Domain Selection
Specify the domains for which the node determines if the specified corners are sharp. Choose the level of the geometry from the Geometric entity level list:
Choose Entire geometry to specify that the attribute determines sharp corners with respect to all domains. The corner refinement also considers corners not adjacent to any domain.
Choose Domain to specify the domains for which you want to determine sharp corners. Choose Manual in the Selection list to select the domains in the Graphics window, choose a named selection to refer to a previously defined selection, or choose All domains to select all domains.
By default, Domain Selections are Active (the Active button is ON).
Boundary Selection
To specify the boundaries, click the Active button to turn it ON and select the boundaries in the Graphics window for which the corner refinement determines the sharp corners. When the boundary selection is Active, the Domain Selection section Active button is automatically turned OFF.
Angle
Use the Minimum angle between boundaries field to specify the minimum angle between a pair of adjacent boundaries in the boundary selection for the refinement factor to apply at the vertex in 2D and edge(s) in 3D between the two boundaries. If a boundary pair is adjacent to one domain on each side (interior boundary) the corner refinement determines the angle(s) on the side(s) corresponding to the specified domain(s).
Select the Filter corners check box (default off) and the settings in the Filter Corner Selection section to filter out a selection of the automatic selection of corners.
Filter Corner Selection
This section is only available when the Filter corners check box is selected.
Use these settings to specify corners to include or exclude from the automatic selection of corners. Choose Manual in the Selection list and click the Active button to turn it ON to select the entities in the Graphics window or from the Selection List, choose a named selection to refer to a previously defined selection, or choose All edges or All points to select all edges or points, respectively. This is useful when another handling of a selection of sharp corners is specified in Corner Properties attributes.
Refinement
Use the Element size scaling factor field to specify a refinement factor (<1) that scales the element size for the vertices in 2D and edges in 3D corresponding to the sharp corners.
For tutorials using Corner Refinement, see:
Boundary Layer Meshing — Exploring the Settings:
Application Library path COMSOL_Multiphysics/Meshing_Tutorials/valve_boundary_layers.
Micromixer: Application Library path COMSOL_Multiphysics/Fluid_Dynamics/micromixer.
Bimetallic Strip in Airflow: Application Library path CFD_Module/Fluid-Structure_Interaction/bimetallic_strip_fsi.