OOF2: The Manual


Periodic (PeriodicBC) — Set the values of a field to be equal along two opposite boundaries.




  • Base class: BC
  • Parameters:

    Type: A Field object.
    Type: An Equation object which can be used in boundary conditions.
    Pair of periodic edge boundaries to which this condition applies Type: A string containing the names of two periodic edge boundaries in a mesh, separated by a space.


Periodic boundary conditions set the values of a component of a Field on a periodic pair of exterior edge boundaries to be the same. A separate boundary condition must be established for each component of a Field that is to be periodic. The value for the boundary parameter must be a string containing the names of two boundaries that constitute a periodic pair: the appropriate periodicity option must have been chosen when the skeleton was created in the skeleton task page and the directions of the boundaries must be opposite. By default, the left and right boundaries will constitute a valid pair if left_right_periodicity was chosen when the skeleton is created, as will the top and bottom boundaries, if top_bottom_periodity was chosen. The GUI presents a pull down menu listing the legal strings, but users of the text interface will need to know the possible values.

The field, field_component, equation, and eqn_component parameters are the same as those for Dirichlet boundary conditions. See that discussion for details. Note that periodic boundary conditions do not have a profile parameter.


    PeriodicBC(field=Displacement, field_component='y',
                equation=Force_Balance, eqn_component='y',
                boundary='left right')

This constrains the y component of the Displacement along the right and left boundaries of the Mesh, making the y component of the Force_Balance periodic in the horizontal direction.