Periodic Condition

The 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 section, which you activate by right-clicking the node and select . With that section, the boundaries which constitute the source and destination surfaces can be manually specified.


	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


	The software usually automatically identifies the boundaries as either source boundaries or destination boundaries, as indicated in the selection list. This works fine for cases like opposing parallel boundaries. In other cases, right-click Periodic Condition and select Manual Destination Selection to control the destination. By default it contains the selection that COMSOL Multiphysics identifies.

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.

Destination Selection

This section is available for specifying the destination boundaries, if needed, when the option is selected in the context menu for the node. You can only select destination boundaries from the union of all source and destination boundaries.

Periodic Condition

Select a — (the default), , or . Select:

•

to make the potential periodic (equal on the source and destination).

•

to make it antiperiodic.

•

(only available with products supporting piezoelectric modeling). Specify the components of the kF (SI unit: rad/m).

Constraint Settings

To display this section, click the button (

) and select in the dialog box.

Orientation of Source

To display this section, click the button (

) and select in the dialog box. For information about the section, see Orientation of Source and Destination in the COMSOL Multiphysics Reference Manual.

Orientation of Destination

This section appears if the setting for in the section is changed from the default value, , and is selected in the dialog box. For information about the section, see Orientation of Source and Destination in the COMSOL Multiphysics Reference Manual.