The interface model defines the way the solver models flow physics across the interface. The available interface model options are:

The periodic options enable a simplified geometry to be used if the full problem features multiple identical regions, as in the following pictures.

Figure 5.1: Periodic Interfaces

The periodic condition ensures that the flow out of one side of the interface automatically appears on the other side. Periodicity is most common for fluid-fluid interfaces, but is also available for all other interface types.