The following list outlines the AFLR4 meshing options along with their default value available through the AIM interface.
Please consult the AFLR4 documentation for default values not present here.
- Proj_Name = NULL
This corresponds to the output name of the mesh. If left NULL, the mesh is not written to a file.
- Mesh_Quiet_Flag = False
Complete suppression of mesh generator (not including errors)
- Mesh_Format = "AFLR3"
Mesh output format. Available format names include: "AFLR3", "VTK", "TECPLOT", "STL" (quadrilaterals will be split into triangles), "FAST".
- Mesh_ASCII_Flag = True
Output mesh in ASCII format, otherwise write a binary file if applicable.
- Mesh_Gen_Input_String = NULL
Meshing program command line string (as if called in bash mode). Use this to specify more
complicated options/use features of the mesher not currently exposed through other AIM input
variables. Note that this is the exact string that will be provided to the volume mesher; no
modifications will be made. If left NULL an input string will be created based on default values
of the relevant AIM input variables.
- ff_nseg
Number of edges or segments on the longest
farfield bounding box side.
If the longest farfield bounding box side is
less then the farfield spacing is set to a
uniform value of ff_spacing=L/ff_nseg.
- min_ncell
Minimum number of cells between two components/bodies.
Proximity of components/bodies
to each other is estimated and surface
spacing is locally reduced if needed. Local
surface spacing is selectively reduced when
components/bodies are close and their
existing local surface spacing would generate
less than the minimum number of cells
specified by min_ncell. Proximity checking is
automatically disabled if min_ncell=1 or if
nprox=0 or if there is only
one component/body defined.
- msfe_all
Global edge mesh spacing scale factor flag.
Edge mesh spacing can be scaled on all surfaces based on discontinuity level
between adjacent surfaces on both sides of the edge. For each surface the level
of discontinuity (as defined by angsfe1 and angsfe2) determines the edge
spacing scale factor for potentially reducing the edge spacing. See sfe_ids and
sfe_list. This option is equivalent to setting sfe_ids equal to the list of all
surface IDS and the edge mesh spacing scale factor weight in sfe_list equal to
one. Note that no modification is done to edges that belong to surfaces with a
grid BC of farfield (ff_ids) or BL intersecting (int_ids).
- nprox
Number of proximity check iterations.
Proximity check iterations are used as a
means to smooth the distribution of spacing
reductions due to proximity. Proximity of
components/bodies to each other is estimated
and surface spacing is locally reduced if
needed. Proximity checking is automatically
disabled if min_ncell=1 or if
nprox=0 or there is only one
component/body defined.
- abs_min_scale
Relative scale of absolute minimum spacing to
reference length. The relative scale of
absolute minimum spacing to reference length
(ref_len) controls the absolute minimum
spacing that can be set on any component/body
surface by proximity checking (see min_ncell
and nprox). Note that the
value of abs_min_scale is limited to be less
than or equal to min_scale.
- BL_thickness
Boundary layer thickness for proximity
checking. Proximity of components/bodies to
each other is estimated and surface spacing
is locally reduced if needed. If
BL_thickness>0 then the boundary layer
thickness is included in the calculation for
the required surface spacing.
- curv_factor
Curvature factor
For surface curvature the spacing is derived from the curvature factor divided
by the curvature.
Curvature = 1 / Curvature_Radius
Spacing = curv_factor / Curvature
The resulting spacing between is limited by the minimum and maximum spacing set
by min_scale and max_scale. Note that if curv_factor=0 then surface curvature
adjustment is not used.
- sfe_all
Global edge mesh spacing scale factor weight.
Edge mesh spacing can be scaled on all surfaces (if msfe_all=1) based on
discontinuity level between adjacent surfaces on both sides of the edge.
For each surface the level of discontinuity (as defined by angsfe1 and angsfe2)
determines the edge spacing scale factor for potentially reducing the edge
spacing. The edge mesh spacing scale factor weight is then used as an
interpolation weight between the unmodified spacing and the modified spacing.
A value of one applies the maximum modification and a value of zero applies no
change in edge spacing. If the global edge mesh spacing scale factor flag,
msfe_all, is set to 1 then that is equivalent to setting AFLR_Edge_Scale_Factor_Weight
on all FACEs to the value sfe_all. Note that no modification is
done to edges that belong to surfaces with a grid BC of farfield (FARFIELD_UG3_GBC) or BL
intersecting. Also, note that the global weight, sfe_all, is not
applicable if msfe_all=0.
- max_scale
Relative scale of maximum spacing to
reference length. The relative scale of
maximum spacing to reference length (ref_len)
controls the maximum spacing that can be set
on any component/body surface.
- min_scale
Relative scale of minimum spacing to
reference length. The relative scale of
minimum spacing to reference length (ref_len)
controls the minimum spacing that can be set
on any component/body surface.
- Mesh_Length_Factor = 1
Scaling factor to compute AFLR4 'ref_len' parameter via:
ref_len = capsMeshLength * Mesh_Length_Factor
where capsMeshLength is a numeric attribute that
must be on at least one body and consistent if on multiple bodies.
ref_len:
Reference length for components/bodies in grid units. Reference length should
be set to a physically relevant characteristic length for the configuration
such as wing chord length or pipe diameter. If ref_len = 0 then it will be set
to the bounding box for the largest component/body of interest.
The parameters ref_len, max_scale, min_scale and abs_min_scale are all used to
set spacing values on all component/body surfaces (those that are not on the
farfield or symmetry plane-if any).
max_spacing = max_scale * ref_len
min_spacing = min_scale * ref_len
abs_min_spacing = abs_min_scale * ref_len
- Mesh_Sizing = NULL
See Mesh Sizing for additional details.