If the flow field is repeated in multiple identical regions, then only one region must be solved, but the boundaries are specified as periodic (via a rotation or translation). A pressure change or mass flow rate may also be imposed for a translationally periodic interface.

Domains can be connected together with a domain interface. This is often useful for connecting static domains together with non-matching grids. For example, hex meshes can be connected to tetrahedral or hybrid meshes. This is a useful strategy for reducing meshing effort. Pitch change can also be included.

You can use domain interfaces to reduce mesh generation effort. The "divide and conquer" principle is useful, where the daunting task of generating a single mesh for the entire domain is divided into the much simpler task of generating a series of meshes that are later connected together.

Domains that have a change in the reference frame (such as rotor-stator) can be connected together. Pitch change can also be included.

Domains with different physical types can be connected together. For example, energy may flow through a fluid-solid interface. These interface types are often generated automatically. Other examples are fluid-porous and solid-porous interfaces.

A domain may contain multiple mesh blocks. Non-matching interfaces can be connected together using a domain interface.

A domain interface can be defined as a thin surface; a thin surface that has its Mass and Momentum set to Conservative Interface Flux can have physics defined across it.