2D BL Meshing

2D BL meshing is a method to create a 2D mesh with or without boundary layers on planar sections defined by sets/groups of edges defining closed loops.

A region is considered closed if it is entirely bounded by edge elements (edge elements should be of type PLOTEL). Element configurations generated by 2D BL meshing are linear quadrilateral (quad4) and triangular (tria3).

Create 2D BL Mesh

Mesh 2D planar areas with boundary layers.

Restriction: Only available in Engineering Solutions when the CFD user profile is loaded.
  1. Open the Utility Browser by clicking View > Utility menu from the menu bar.
  2. Under Generate Mesh, click Generate 2D BL Mesh.
    The 2D Boundary Layer Mesh dialog opens.
  3. Select the 2D Native BL (planar) tab.
  4. In the Default Value fields, enter the default values that apply to most components.
    1. For 1st Layer Thickness, enter the thickness for the first layer of elements.
    2. For Growth Rate, enter the boundary layer thickness growth rate from layer to layer.
    3. For Bound Type, select a boundary layer type.
      Choose Wall to generate boundary layers along the component edges. No boundary layers are generated when Bound Type is set to Farfield, In/Outlet, and Symmetry.
      Note:

      Edge elements in collectors having Bound Type defined as Farfield, In/Outlet, and Symmetry will be used to define the geometry, but they will not dictate element size/density.



      Figure 1.
  5. Click Add collector to select or add components containing edge elements (elem type PLOTEL) that define the boundaries of the 2D section.
    Default values (1st Layer Thickness, Growth Rate and Bound Type ) are assigned to the selected components.


    Figure 2.
  6. To maintain the node seeding on the edge without BL as much as possible, select the Retain node seeding on edge w/o BL checkbox.
    The nodes on the non-BL boundary, which are located inside the BL, will not be maintained. Only the nodes which are located inside of the BL will be maintained.
  7. In the Number of boundary layers field, enter the number of boundary layers to generate.
  8. To control the aspect ratio of boundary layer elements by refining the edges to generate boundary layer elements that satisfy the Max perimeter element aspect ratio value, select the Allow boundary node insertion checkbox.


    Figure 3.
  9. To control the aspect ratio of boundary layer elements by boundary node movement so that generate boundary layer elements will satisfy the Max perimeter element aspect ratio value, select the Allow boundary node movement checbox.


    Figure 4.
  10. Click Generate 2D BL mesh.
The 2D BL mesh is generated.






Figure 5.