11.10.1.1 Unstructured Geometry Extensions

Figure 11.10.1.1-1 shows that unstructured grid geometry supports two extensions: hinge nodes and finite elements.

Figure 11.10.1.1-1 Unstructured grid geometry with extensions.

Unlike grids based on columns, the hinge node faces are not defined implicitly. Instead any cell face to which it is desired to associate hinge nodes must be specified as a hinge node face. Hinge nodes are an example of explicit interpolation on a face, in which the surface is replaced by a triangulated surface using the additional point geometry of the hinge node. The unstructured grid geometry also supports finite element extensions, as shown. The unstructured grid geometry supports the unstructured grid representation and also arises in the general purpose grid as a patch. A similar construction is used when defining the truncation cells for the truncated column-layer grids.