When mapping CFD results onto the Mechanical application face(s) the Mechanical nodes are projected on to the CFD face. All the Mechanical application face nodes will map to the CFD face according to the following rules:
Project normal to the CFD mesh faces.
If rule a fails, project to the closest edge.
If rule b. fails, project to the closest node on the CFD face.
Rule c. will always work, so in the end every node will get some kind of mapping. However the most accurate load mapping occurs for nodes projected normal to the mesh face. The percentage of the Mechanical application nodes that mapped successfully using rule a. above is reported in the diagnostics. When the Mechanical application mesh is very coarse, there can be some misses near the edges of the CFD boundary. However all nodes become mapped eventually. The accuracy of force transfer improves as the Mechanical application mesh is refined.
When mapping CFD domain results onto the corresponding Mechanical Application body selection(s), all the Mechanical Application nodes that cannot be mapped to the CFD domain will be set to the average temperature.