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FEM Mesh Boundary Layer

In one sentence: Add prismatic boundary layer elements adjacent to selected wall faces in a Gmsh mesh for fluid flow analysis.

Overview

Workbench: FEM
Menu: FEM → Mesh → FEM Mesh Boundary Layer

Adds a prismatic boundary layer stack to selected faces in a Gmsh mesh. Boundary layers are thin, structured layers essential for CFD analysis to resolve the velocity gradient in the viscous sublayer.

Parameters

Parameter Description
Start Size Thickness of the first layer (closest to wall)
Growth Rate Ratio between successive layer thicknesses (e.g. 1.2)
Number of Layers Total number of prismatic layers
References Faces to apply the boundary layer to

Choosing parameters

For turbulent flow at moderate Reynolds numbers: - First layer at y⁺ ≈ 1 (viscous sublayer) or y⁺ ≈ 30–100 (log-law, wall functions). - Growth rate of 1.2–1.3 is typical. - 10–20 layers is common.

Common mistakes and pitfalls

Gmsh only

Boundary layers are a Gmsh feature and cannot be added to Netgen meshes.

See also