Periodic Condition
The Periodic Condition node adds a periodic boundary condition that can be used to reduce the model size by using symmetries and periodicities in the geometry and physics interfaces being modeled. The condition is found under the Connections submenu.
Periodicity Settings
Select a Type of periodicity: Continuity (the default), Antiperiodicity, Floquet periodicity (Bloch periodicity), Cyclic symmetry, or User defined. For User defined, select one or more of the following check boxes:
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 Periodic displacement in the x direction
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Periodic displacement in the y direction
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 Periodic displacement in the z direction (3D only)
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 Periodic pressure 
For details, see the Periodic Condition description in Pressure Acoustics.
To get correct behavior of the Periodic Condition, in particular the Floquet periodicity and the Cyclic symmetry conditions, it is recommended that the source and destination meshes are identical. This can be achieved using the Identical Mesh mesh feature. When the Periodic Condition stretches across regions with a mix of default material models, PMLs, background pressure fields, or background acoustic fields, it is recommended to add one Periodic Condition for each set of such boundaries.