By default, a Delaunay based method is used to insert points into an unstructured domain when it is initialized. Alternatively, you may select the Advancing Front, Advancing Front Ortho, or Thin Surface Interpolation methods.
The Algorithm pull-down provides a choice of four methods for filling the isotropic portion of the domain:
Thin Surface Interpolation is intended to be used on long thin rectangular surfaces (such as the blunt trailing edge of a wing), where using diagonalized structured domains is not possible or practical. Similar to structured domains, T-Rex is not available for domains using Thin Surface Interpolation and source influence only affects the spacing distribution on the bounding connectors.
Caution: Since Thin Surface Interpolation is intended as an alternative to structured domain initialization, the attributes in the Cells frame, Quads frame, T-Rex tab, and Size Field tab have no impact. However, these attributes are used with the Advancing Front Ortho algorithm if Thin Surface Interpolation fails due to one of the constraints below.
Additionally, Thin Surface Interpolation can only be applied to domains that meet certain constraints, otherwise the algorithm defaults to Advancing Front Ortho and a warning message is printed to the Messages window. Please click the Thin Surface Interpolation Constraints button below to view a table listing the constraints and their meanings.
The figure below shows a comparison of the grid characteristics produced by the four algorithms using both the Triangles and Triangles and Quads cell type options. Note the differences between the Advancing Front Ortho and Thin Surface Interpolation algorithms when using computationally unbalanced domains.