Periodic Condition
The Periodic Condition splits its selection into a source group and a destination group (the Destination Selection section is optional). It ensures that the flow and temperature fields at the source and destination boundaries are continuous. This corresponds to a situation where the geometry is a periodic part of a larger geometry. Flow characteristics at the boundary, described in Plane Wave Analysis of Inviscid Flow, are utilized to implement the continuity of the flow and temperature fields. If the boundaries are not parallel to each other, the velocity vector is automatically transformed.
If the boundaries are curved, the orientation of the source must be specified manually (see Orientation of Source).
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.
Destination Selection
This section is available for specifying the destination boundaries, if needed, when the Manual Destination Selection option is selected in the context menu for the Periodic Condition node. You can only select destination boundaries from the union of all source and destination boundaries.
Orientation of Source
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.
Orientation of Destination
This section appears if the setting for Transform to intermediate map in the Orientation of Source section is changed from the default value, Automatic, and Advanced Physics Options is selected in the Show More Options dialog box. For information about the Orientation of Destination section, see Orientation of Source and Destination in the COMSOL Multiphysics Reference Manual.
Mapping Between Source and Destination
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 Mapping Between Source and Destination section, see Mapping Between Source and Destination in the COMSOL Multiphysics Reference Manual.