Advancing Layer Mesher Reference

Stretching Function

Selects the stretching function to use in calculating the thickness of each cell layer within the prism layer.

• Geometric Progression—The thickness of each cell layer is calculated using a geometric progression that is based around a constant size ratio.
• Hyperbolic Tangent— The thickness of each cell layer is calculated using a hyperbolic tangent stretching function.

Distribution Mode

Selects the stretching mode to use in specifying the relative size parameters that the stretching function requires.

• Stretch Factor—The definition of the stretch factor depends on which stretching function is being used. Adds the Prism Layer Stretching node for global and custom settings.
• Wall Thickness— Sets the thickness of the near-wall cell layer. Thicknesses of the remaining layers are distributed according to a calculated stretch factor. Adds the Thickness of Near Wall Prism Layer node for global and custom settings.
• Thickness Ratio—Sets the ratio of the thickness of the cell layer furthest from the wall to the thickness of the cell layer nearest the wall. Adds the Prism Layer Thickness Ratio node for global and custom settings. You can define the Prism Layer Thickness Ratio using a constant value or global parameter (see Global Parameters).

Advancing Layer Mesher Expert Properties

The following table contains expert properties that are specific to the advancing layer mesher model. Common volume mesher expert properties are also available. If the mesher is removed from an Automated Mesh operation, any user defined settings will be saved and restored when the mesher is restored.

Surface Element Type

Specifies the shape of the faces on the surface.

• Input—Creates a volume mesh that matches the input surface which could contain triangles, quads, or a mix of triangles and quads.
• Polygon—Dualizes the triangular faces of the input mesh (creating typical polygonal cells). Quadrilateral faces in the input mesh are not changed. The resulting volume mesh will match the dualized polygon cells and the input quadrilateral cells.

Generate Standard Cells Only

Lets you choose if only standard cells are produced or not. In PBM, this property is activated automatically when the Tetrahedral mesher is selected as the core mesher.

• Activated—The mesh that is generated can only contain cells that are tetrahedral, hexahedral, wedges, and pyramids.
• Deactivated—The mesh that is generated can contain polyhedral cells.

Sharp Edge Refinement

When activated, this option automatically improves the mesh near sharp edges. Typically, sharp edges such as trailing edges on a wing are problematic for mesh generators as they rely on surface normal vectors to guide them in creating cells next to the surface. Sharp Edge Refinement adds additional surface normal vectors around the sharp edge.

Sharp Edge Refinement is applied to edges where the internal angle between faces is less that than 150 degrees, including baffle edges. Some edges are excluded from the refinement due to topological features—for example, single sharp edges or junctions of more than three sharp edges.

Sharp Edge Refinement is a global property, which means that it is applied to all part curves. When using Sharp Edge Refinement in the parallel meshing mode, check for warnings about surface mesh quality in the Output window. If the mesh fails to generate, switch off Sharp Edge Refinement or improve the surface mesh quality.

Limit Aspect Ratio

Allows you to limit the aspect ratio of prism cells, which is the ratio of the total prism layers thickness to the base size. When activated, the Advancing Layer Mesher stops building prism layers when the aspect ratio reaches the specified limit. The aspect ratio is computed based on local face sizes. Therefore, the final shape of the boundary layer depends on the face size distribution across the input surface.

Setting a limit for the aspect ratio can improve volume transitions at the boundary between prism layers and the core mesh and also reduce the prism cell count.

You can specify a limiting value for all parts assigned to the mesh operation using the Default Controls > Limit Aspect Ratio node, which appears when you activate the Limit Aspect Ratio property on the Advancing Layer Mesher node. You can then customize the limit aspect ratio for specific surfaces or volumes using surface or volume controls (see Specifying a Limit for the Aspect Ratio).

If you wish to specify the limit aspect ratio only for specific surfaces and volumes, without specifying a global value for the entire operation, you can define the Limit Aspect Ratio for the relevant custom controls without setting the Default Controls > Limit Aspect Ratio node.

For comparision with the Near Core Layer Aspect Ratio, available for the Prism Layer Mesh see Near Core Layer Aspect Ratio.

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