12.8 Adding a boundary layer to a tetrahedral mesh

Product: Abaqus/CAE

Benefits: You can now add a boundary layer composed of one or more layers of wedge elements extruded from the exterior faces surrounding a tetrahedral mesh. Adding layers of small elements along the walls allows improved analysis of boundary effects in fluid flow and heat transfer analyses.

Description: In previous releases of Abaqus, the construction of a boundary layer near external surfaces would have been a tedious process. Now you can easily specify a boundary layer when you select the mesh controls for a region. The thinnest layers of wedge elements are at the walls, where boundary effects are greatest; and you can increase the layer thickness toward the interior of the model.

When you assign mesh controls to regions and choose a tetrahedral element shape, the option to insert a boundary layer appears near the bottom of the Mesh Controls dialog box. Click the Assign Controls button to access the Boundary Layer dialog box so that you can define the layers of wedge elements. You must enter the following information:

The height (thickness) of the element layer adjacent to the walls.
A growth factor that determines the increase in height of each successive layer inward from the walls.
The number of wedge element layers.

Once you complete this information, Abaqus/CAE calculates and displays the total thickness of the boundary layer that will be created. You can select Inactive faces—model faces that should not include the boundary layer—such as faces that represent inlets, outlets, and symmetric model constraints, and you can choose to create a set containing the boundary elements. Figure 12–5 shows the settings in the Boundary Layer dialog box and a detail of a pipe intersection model meshed with the selected parameters. The pipe end shown was selected as an inactive face, so the boundary layer is shown.

Figure 12–5 The Boundary Layer dialog box and resulting mesh layers.

Abaqus/CAE Usage:

Mesh module:
    MeshControls: Element shape: Tet: toggle on Insert boundary layer, and click Assign Controls

Reference:

Abaqus/CAE User's Manual

“Adding layers of wedge elements to tetrahedral mesh boundaries,” Section 17.18.12