AddPeriodicBCAction

Periodic boundary conditions enforce value constraints on separate boundaries in the mesh. This capability is useful for modeling quasi-infinite domains and systems with conserved quantities.

MOOSE has full support for Periodic BCs in

1D, 2D, and 3D.
With mesh adaptivity.
Can be restricted to specific variables.

Supports arbitrary translation vectors for defining periodicity.

Automatic Periodic Boundary Detection (recommended)

[BCs]
  [./Periodic]
    [./all]
      variable = u
      auto_direction = 'x y'
    [../]
  [../]
[]

/opt/civet/build_0/moose/test/tests/bcs/periodic/auto_periodic_bc_test.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 50
  ny = 50
  nz = 0
  xmax = 40
  ymax = 40
  zmax = 0
  elem_type = QUAD4
[]

[Variables]
  active = 'u'

  [./u]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[AuxVariables]
  [./periodic_dist]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[Kernels]
  active = 'diff forcing dot'

  [./diff]
    type = Diffusion
    variable = u
  [../]

  [./forcing]
    type = GaussContForcing
    variable = u
  [../]

  [./dot]
    type = TimeDerivative
    variable = u
  [../]
[]

[AuxKernels]
  [./periodic_dist]
    type = PeriodicDistanceAux
    variable = periodic_dist
    point = '4 6 0'
  [../]
[]

[BCs]
  [./Periodic]
    [./all]
      variable = u
      auto_direction = 'x y'
    [../]
  [../]
[]

[Executioner]
  type = Transient
  dt = 1
  num_steps = 20
  solve_type = NEWTON
[]

[Outputs]
  execute_on = 'timestep_end'
  file_base = out_auto
  exodus = true
[]

Translation Periodic Boundaries

[BCs]
  [./Periodic]
    [./x]
      variable = u
      primary = 3
      secondary = 1
      translation = '40 0 0'
    [../]

    [./y]
      variable = u
      primary = 0
      secondary = 2
      translation = '0 40 0'
    [../]
  [../]
[]

/opt/civet/build_0/moose/test/tests/bcs/periodic/periodic_bc_test.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 50
  ny = 50
  nz = 0
  xmax = 40
  ymax = 40
  zmax = 0
  elem_type = QUAD4
[]

[Variables]
  [./u]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[Kernels]
  [./diff]
    type = Diffusion
    variable = u
  [../]

  [./forcing]
    type = GaussContForcing
    variable = u
  [../]

  [./dot]
    type = TimeDerivative
    variable = u
  [../]
[]

[BCs]
  [./Periodic]
    [./x]
      variable = u
      primary = 3
      secondary = 1
      translation = '40 0 0'
    [../]

    [./y]
      variable = u
      primary = 0
      secondary = 2
      translation = '0 40 0'
    [../]
  [../]
[]

[Executioner]
  type = Transient
  dt = 1
  num_steps = 20
  solve_type = NEWTON
[]

[Outputs]
  execute_on = 'timestep_end'
  file_base = out
  exodus = true
[]

Function Transform Periodic Boundaries

[Functions]
  [./tr_x]
    type = ParsedFunction
    value = -x*cos(pi/3)
  [../]

  [./tr_y]
    type = ParsedFunction
    value = x*sin(pi/3)
  [../]

  [./itr_x]
    type = ParsedFunction
    value = -x/cos(pi/3)
  [../]

  [./itr_y]
    type = ParsedFunction
    value = 0
  [../]
[]

[BCs]
  [./Periodic]
    [./x]
      primary = 1
      secondary = 4
      transform_func = 'tr_x tr_y'
      inv_transform_func = 'itr_x itr_y'
    [../]
  [../]
[]

/opt/civet/build_0/moose/test/tests/bcs/periodic/trapezoid.i

[Mesh]
  file = trapezoid.e
  uniform_refine = 1
[]

[Functions]
  [./tr_x]
    type = ParsedFunction
    value = -x*cos(pi/3)
  [../]

  [./tr_y]
    type = ParsedFunction
    value = x*sin(pi/3)
  [../]

  [./itr_x]
    type = ParsedFunction
    value = -x/cos(pi/3)
  [../]

  [./itr_y]
    type = ParsedFunction
    value = 0
  [../]
[]

[Variables]
  [./u]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[Kernels]
  [./diff]
    type = Diffusion
    variable = u
  [../]

  [./forcing]
    type = GaussContForcing
    variable = u
    x_center = 2
    y_center = -1
    x_spread = 0.25
    y_spread = 0.5
  [../]

  [./dot]
    type = TimeDerivative
    variable = u
  [../]
[]

[BCs]
  [./Periodic]
    [./x]
      primary = 1
      secondary = 4
      transform_func = 'tr_x tr_y'
      inv_transform_func = 'itr_x itr_y'
    [../]
  [../]
[]

[Executioner]
  type = Transient
  dt = 0.5
  num_steps = 6
  solve_type = NEWTON
[]

[Outputs]
  execute_on = 'timestep_end'
  file_base = out_trapezoid
  exodus = true
[]

Input Parameters

active__all__ If specified only the blocks named will be visited and made active
Default:__all__
C++ Type:std::vector
Options:
Description:If specified only the blocks named will be visited and made active
auto_directionIf using a generated mesh, you can specifiy just the dimension(s) you want to mark as periodic
C++ Type:std::vector
Options:
Description:If using a generated mesh, you can specifiy just the dimension(s) you want to mark as periodic
inactiveIf specified blocks matching these identifiers will be skipped.
C++ Type:std::vector
Options:
Description:If specified blocks matching these identifiers will be skipped.
inv_transform_funcFunctions that specify the inverse transformation
C++ Type:std::vector
Options:
Description:Functions that specify the inverse transformation
primaryBoundary ID associated with the primary boundary.
C++ Type:BoundaryName
Options:
Description:Boundary ID associated with the primary boundary.
secondaryBoundary ID associated with the secondary boundary.
C++ Type:BoundaryName
Options:
Description:Boundary ID associated with the secondary boundary.
transform_funcFunctions that specify the transformation
C++ Type:std::vector
Options:
Description:Functions that specify the transformation
translationVector that translates coordinates on the primary boundary to coordinates on the secondary boundary.
C++ Type:libMesh::VectorValue
Options:
Description:Vector that translates coordinates on the primary boundary to coordinates on the secondary boundary.
variableVariable for the periodic boundary
C++ Type:std::vector
Options:
Description:Variable for the periodic boundary

References

Automatic Periodic Boundary Detection ( recommended )
Translation Periodic Boundaries
Function Transform Periodic Boundaries
Input Parameters
References

Application Usage

Physics and Syntax

Application Development

Framework Development

MOOSEDocs

Infrastructure

Questions

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