The Pressure Acoustics Interface > The Pressure Acoustics, Frequency Domain Interface > Periodic Condition

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. This feature works well for cases like opposing parallel boundaries. In other cases use a Destination Selection subnode to control the destination. By default it contains the selection that COMSOL Multiphysics identifies.
Periodicity Settings
Select a Type of periodicityContinuity (the default) or Antiperiodicity.
Constraint Settings
To display this section, click the Show button () and select Advanced Physics Options.
Orientation of Source
For information about the Orientation of Source section, see Orientation of Source and Destination.