Periodic Condition
The Periodic Condition node defines periodicity or antiperiodicity between two boundaries. If required, activate periodic conditions on more than two boundaries, in which case the Periodic Condition tries to identify two separate surfaces that can each consist of several connected boundaries. For more complex geometries, it might be necessary to use the Destination Selection subnode. With this subnode the boundaries which constitute the source and destination surfaces can be manually specified. The Destination Selection subnode is available from the context menu (right-click the parent node) as well as from the Physics toolbar, Attributes menu.
When this feature is used in conjunction with a Sector Symmetry feature on connected boundaries, wherever the sector symmetry boundaries connect with the periodic boundaries, the same periodic condition feature cannot be used on both sides. At least two periodic condition features are required for the model to compute correctly.
Boundary Selection
When using nonconforming meshes on the source and destination of a periodic boundary pair, for numerical stability, a finer mesh should be applied on the destination side. Use conforming meshes if possible.
Periodic Condition
Select a Type of periodicity — Continuity (the default), Antiperiodicity, or Floquet periodicity. Select:
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Continuity to make the electric potential periodic (equal on the source and destination).
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Antiperiodicity to make it antiperiodic.
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Floquet periodicity (only available with products supporting piezoelectric modeling). Specify the components of the k-vector for Floquet periodicity kF (SI unit: rad/m).
Constraint Settings
To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box.
For information about the Orientation of Source section, see Orientation of Source and Destination in the COMSOL Multiphysics Reference Manual.