Periodic Condition
The Periodic Condition node adds a periodic boundary condition. This periodicity can be continuous (the default) so that u(x0) = u(x1) or antiperiodic so that u(x0) = −u(x1) and can control to which dependent variables the periodic condition applies.
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 add a Destination Selection subnode to control the destination. By default it contains the selection that COMSOL Multiphysics identifies.
Periodic Condition
Select a Type of periodicity: Continuity (the default) to make the dependent variables equal, or Antiperiodicity to make them antiperiodic: u(x0) = −u(x1).
For each dependent variable in the PDE, choose to apply the periodic condition by selecting, for example, the Apply condition on variable u1 check box. By default, the periodic condition applies to all dependent variables.
Constraint Settings
To display this section, click the Show button () and select Advanced Physics Options. This section contains settings for specifying the type of constraint and whether to use a pointwise or weak constraint. See Constraint Settings for more information.
Orientation of Source
To display this section, click the Show button () and select Advanced Physics Options. For information about the Orientation of Source section, see Orientation of Source and Destination.
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Periodic Boundary Conditions
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Working with Geometric Entities