In Release 12.0, thin surfaces have been implemented to enable the modeling of physics (such as heat transfer, mass transfer, and momentum losses) across thin-surfaces. In previous releases, the Create Thin Partner option created two independent walls, which did not enable physics to be implemented. Starting with Release 12.0, you can model a thin surface either as:
A boundary condition (for details see Default Boundary Condition in the CFX-Pre User's Guide)
A domain interface with the physics modeled across the interface.
The types of domain interfaces you can define as thin surfaces depends on the domains involved: