Troubleshooting Boundary Layer Mesh Generation
The boundary layer meshing algorithm is sensitive to the topology of the model geometry. If you get an error when trying to build a Boundary Layers node, try the following:
Remove unnecessary interior boundaries, such as boundaries resulting from Boolean operations of geometry objects that do not separate materials or physics. Sometimes, it is possible to draw the geometry differently to avoid the boundaries. Another alternative is to use Ignore Faces to ignore the boundaries (Ignore Edges in 2D). The third alternative to do this is to mark these boundaries as mesh control entities in the geometry sequence. Once you have removed unnecessary boundaries, mesh the domains using a tetrahedral or a swept mesh. When the domains are meshed, the mesh control entities are automatically removed, and you can insert boundary layers, ignoring the interfering boundaries. See Controlling the Mesh Size Using Mesh Control Entities for more information.
Use boundary layer mesh Trimming instead of Splitting. By default, the boundary layer mesher creates a boundary layer split at each sharp corner in 2D and along each sharp edge in 3D. To still resolve the mesh at the sharp corners where the mesh is trimmed, add a Corner Refinement. This set up is the default for the Physics-Controlled mesh set up for fluid flow.
See Information, Warning, and Error Nodes for tips on how to inspect problematic areas.