When the points in a boundary condition profile do not exactly match the underlying CFX mesh, the CEL functions that evaluate the associated expressions use a "cloud of points" method, using the closest three points, to interpolate the profile data onto the CFX mesh (see Three Dimensional Interpolation). This can be inaccurate for some profiles and meshes, particularly those situations where the profile is coarse and the mesh is fine, or where relatively thin structures (like blades) are present.
To improve accuracy in these situations, the profile mapping operation maps the profile data onto the selected CFX mesh regions explicitly, using a more accurate mapping algorithm to interpolate the profile data onto the CFX mesh.
After the mapping process is complete, you are presented with the diagnostics for the mapping operation. If any of the "Overlap face/area/node" statistics are significantly below 100% then you should check the resulting profile carefully to ensure that the mapping setup has worked as expected.
The procedure for mapping profile data involves the following steps:
Set the profile transformation option to
Mapped Expansion.Specify the Mesh Regions onto which the profile data needs to be mapped.
Leave Add Node Mapping Status Variable selected to create variable
Node Mapping Status, which has a value of 1 for a mapped node and 0 for an unmapped node. This variable can be visualized in CFX-Pre (by coloring by a profile variable) or by importing the profile into CFD-Post.
The following limitations apply to profile data mapping:
A coordinate frame defined in the profile is ignored; the nodal coordinates, when passed to the mapper, and the resulting mapped profile, are assumed to be in the global frame. However, the coordinate frame definition is still included in the mapped file.
Failures in the mapping process might occur if the selected mesh regions include regions from both sides of a periodic boundary. If such a failure occurs then you can map onto subsets of the mesh regions and combine the resulting profile files as necessary.
Mapping is performed in a way that preserves profiles for solution variables; flow quantities are not necessarily conserved.