Periodic boundary condition¶
The Periodic boundary condition defines a special type of symmetry that obeys cyclic/repeating condition of the flow across the boundary surface. For this condition, it is then mandatory to select two boundary faces that will be treated as if they are physically connected. The flow exiting/entering from one face then enters/exits the other face.
Some examples of such a flow can be, heat exchanger tube bundles or a swept vane pump impeller.
For this boundary condition the faces do not need to be of the same orientation. But, the two periodic boundary condition faces must have similar area to within a given tolerance.