Source Surface Anisotropic Sizing Function

The Source Surface Anisotropic Sizing Function, generates a tensor field based upon the geometric shape of the given surfaces, which can be used to generate anisotropic tet elements. This sizing function supports 2 factors for anisotropy. Additionally, if the specified surfaces are cylindrical or conical, 3 factors for anisotropy are supported. If multiple surfaces are given, a sizing tensor at a location in the field is defined by the closest surface.

For anisotropy with 2 factors, one factor is applied in the direction normal to a surface, and the other factor is applied in the orthogonal directions. For anisotropy with 3 factors, one factor is applied in the direction normal to a surface, and one factor is applied in the direction of the axis for The cylindrical surface, and the third factor is applied in the direction orthogonal to the first 2 directions.

The following command is used to generate an anisotropic tensor field:

Volume <range> Sizing Function Source Surface <id> Near <size> [theta <size> | Theta_interval <count> [Theta_axis <axis>]] Growth_factor <factor>

The Near size is the factor applied in the direction normal to the surface
The optional Theta size is the factor applied in the direction of the cylindrical surface axis
The optional Theta_interval count is the number of elements to create in the direction of the cylindrical surface axis
The optional Theta_axis axis provides the axis for a cylindrical surface as an alternative to computing one from the input surface
The Growth_factor is the rate of change in the Near size as the location moves away from the surface

The factors not specified above will come from the size applied to the volume.

Below are a couple examples of using this anisotropic sizing function.

The following example uses 2 size factors to create an anisotropic tensor field.

Figure 1: Anistropy from 2 source surfaces

volume 1 size 0.03
volume 1 sizing function source surface 7 8 near 0.003 growth .2
volume 1 scheme tetmesh
mesh volume 1

The following example uses 3 size factors to create an anisotropic tensor field.

Figure 2: Anistropy from 1 source surface

create Cylinder height 0.05 radius 0.1
create Cylinder height 0.05 radius 0.08
subtract volume 2 from volume 1
volume 1 scheme tetmesh
volume 1 size 0.01
Volume 1 Sizing Function Source Surface 1 7 Near 0.004 theta 0.025 Growth_factor 0.01
mesh surface all