AFLR4 Analysis Interface Module (AIM)
AFLR4 Analysis Interface Module (AIM)
AIM Attributes

The following list of attributes are available to guide the mesh generation with the AFLR4 AIM.

Predefined AFLR Grid BC string values are:

AFLR_GBC String Description
FARFIELD_UG3_GBC farfield surface
same as a standard surface except w/AFLR4
STD_UG3_GBC standard surface
-STD_UG3_GBC standard BL generating surface
BL_INT_UG3_GBC symmetry or standard surface
that intersects BL region
TRANSP_SRC_UG3_GBC embedded/transparent surface
converted to source nodes by AFLR
TRANSP_BL_INT_UG3_GBC embedded/transparent surface
that intersects BL region
TRANSP_UG3_GBC embedded/transparent surface
-TRANSP_UG3_GBC embedded/transparent BL generating surface
TRANSP_INTRNL_UG3_GBC embedded/transparent surface
converted to internal faces by AFLR
FIXED_BL_INT_UG3_GBC fixed surface with BL region
that intersects BL region

Within AFLR4 the grid BC determines how automatic spacing is applied. Their are four basic Grid BC types that are each treated differently.

  1. Faces/surfaces that are part of the farfield should be given a FARFIELD_UG3_GBC Grid BC. Farfield faces/surfaces are given a uniform spacing independent of other faces/surfaces with different Grid BCs.

  2. Faces/surfaces that represent standard solid surfaces should be given either a STD_UG3_GBC or -STD_UG3_GBC (BL generating) Grid BC. Standard surfaces are given a curvature dependent spacing that may be modified by proximity checking.

  3. Faces/surfaces that intersect a BL region should be given either a BL_INT_UG3_GBC (standard boundary surface) or TRANSP_BL_INT_UG3_GBC (embedded/ transparent surface with volume mesh on both sides) Grid BC. A common example for the BL_INT_UG3_GBC Grid BC is a symmetry plane. Faces/surfaces set as BL intersecting surfaces are excluded from auto spacing calculations within AFLR4 and use edge spacing derived from their neighbors.

  4. Surfaces set as transparent surfaces will have a volume mesh on both sides. They can have free edges and can have non-manifold connections to standard solid surfaces and/or BL intersecting surfaces. Vertices in the final surface mesh are not duplicated at non-manifold connections. Transparent surfaces use curvature driven surface spacing as used on standard solid surfaces. However, at non-manifold connections with standard solid surfaces they inherit the surface spacing set on the solid surface they are attached to. They are also excluded from proximity checking. Typical examples of transparent surfaces include wake sheets or multi-material interface surfaces.

  1. If defined by EGADS attribute AFLR4_Cmp_ID then attribute sets component identifier.
  2. Else, if multiple bodies are defined in the EGADS model then bodies index is used to set component identifier.
  3. Else, component identifiers are set an index based on topologically closed surfaces/bodies of the overall configuration.