Curvature and Proximity Size Function

This size function controls how the mesh size is distributed on a surface or within a volume.

The following properties define the curvature size function.

Minimum size

The global minimum size to be used in curvature and proximity size function mesh calculations. Some element sizes may be smaller than this based on local feature sizes or other geometric anomalies. Specify a value greater than 0 or accept the predefined setting.

Maximum face size

The maximum size to be used for surface meshing. Element faces may be larger than this size based on hard edge sizes or floating point arithmetic. Specify a value greater than 0 or accept the predefined setting.

Maximum size

The maximum size to be used in curvature and proximity size function mesh calculations. Specify a value greater than 0 or accept the predefined setting.

Growth rate

Represents the increase in element edge length with each successive layer of elements. For example, a growth rate of 1.2 results in a 20% increase in element edge length with each succeeding layer of elements. Specify a value from 1.0 to 5.0 or accept the predefined setting. The predefined setting is 1.2.

Curvature normal angle

The maximum permitted angle that one element edge may span. Specify a positive value of up to 3.14 radians (180 degrees), or accept the predefined setting. The predefined setting is 0.31416 radians (or 18 degrees).

Proximity size function sources

Determines whether regions of proximity between faces and/or edges are considered when proximity size function calculations are performed. Choose one of the following:

  • Edges: Considers edge-edge proximity. Face-face and face-edge proximity are not considered.
  • Faces: This is the predefined setting. Considers face-face proximity between faces. Face-edge and edge-edge proximity are not considered (that is, the trailing edge of fluid around wings will not be captured with this setting).
  • Faces and edges: Considers face-face and edge-edge proximity. Face-edge proximity is not considered.

Number of cells across gap

The minimum number of layers of elements to be generated in the gaps. You can specify a value from 1 to 100 or accept the predefined setting. The predefined setting is 1. The value of Number of cells across gap is an approximation:

  • The value may not be satisfied exactly in every gap. When sweeping, interval assignment may change the number of divisions (that is, elements or cells) in a gap.
  • You must define minimum size such that it allows the specified Number of cells across gap to be achieved. For example, if you have a gap of 1 mm, the minimum size is 0.5 mm, and the value of Number of cells across gap is 3, only 2 cells can be generated in the gap.
  • Faces and edges: Considers face-face and edge-edge proximity. Face-edge proximity is not considered.

Maximum boundary layers

Boundary layers improve the mesh to resolve high gradients of velocity or temperature near the wall for fluid flow simulations. For fluid flow and fluid-solid heat transfer simulations, the default maximum boundary layers are 3. You can modify the number of boundary layers, increasing the number of layers improves accuracy and increases the solution time.