Periodic Condition

The node can be used to define periodicity for the mass transport between two sets of boundaries. The node prescribes continuity in the concentration and the mass flux between the “source” and the “destination” side, respectively. Note that these names are arbitrary and does not influence the direction in which mass is transported. It is dictated by mass transfer equations in the adjacent domains.

The node can be activated on more than two boundaries, in which case the feature tries to identify two separate surfaces that each consist of one or several connected boundaries.

For more complex geometries, it might be necessary to specify the destination selection manually. To do so, right-click the node and choose . You can then specify the boundaries that constitute the destination surfaces in the section.

To display this section, click the button (

) and select in the dialog box. This section contains settings for specifying the type of constraint and whether to use a pointwise or weak constraint. See Constraint Settings in the COMSOL Multiphysics Reference Manual for more information.

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.

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.

To display this section, click the button (

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

For an example of using a periodic condition, see this application example: