STAR-CCM+ requires the existence of an interface between all regions in order to transfer the appropriate mass and energy quantities during the calculation. For this example, we will need to create a contact-type interface between the fluid and solid regions. This involves creating a so-called "in-place interface" between the wall boundaries enclosing each of the two regions, and then defining this interface as being of an appropriate "contact" type for fluid-solid heat transfer.
The above step will create a new node within each Boundaries node. A new boundary node called Air-Interface [In-place 1] will appear in the Boundaries node of the Fluid region node, and another one called Fin-Interface [In-place 1] will appear in the Boundaries node of the Solid region node. These boundaries will form the connection between the fluid and solid regions once the flow initialization step has been performed and will supersede the original wall boundaries forming the connection.
In addition to the new in-place boundaries, a new folder node named Interfaces will appear in the object tree. Within it, an interface node called In-place 1 will be created. To view the properties of the new interface:
The properties of the interface will now become accessible.
The interface type is automatically set to Contact Interface as this is the only valid option for interfaces between fluid and solid regions. Additional settings such as a heat transfer resistance value between the two regions can also be set via the Conditions and Values nodes of the interface node. To delete or remove the interface, you would delete its node from the Interfaces node, automatically removing the appropriate in-place boundary nodes. For this exercise, however, do not delete the interface.
