PeriodicFunction

Provides a periodic function by repeating a user-supplied base function in time and/or any of the three Cartesian coordinate directions

Description

The PeriodicFunction takes a user-supplied base function, and periodically repeats that function in time or any of the three Cartesian coordinate directions. The function can be repeated in any combination of these directions or time.

The resulting function repeats the base function's behavior over the interval from 0 to the specified period in a given dimension. This is repeated indefinitely, and is also repeated (rather than mirrored) for negative values of the coordinates or time.

Example Input Syntax

[Functions]
  [periodic_xyzt]
    type = PeriodicFunction
    base_function = base_xyzt
    period_x = 1
    period_y = 1
    period_z = 1
    period_time = 1
  []
[]

Input Parameters

base_functionThe function used as a basis for the generated periodic function.
C++ Type:FunctionName
Controllable:No
Description:The function used as a basis for the generated periodic function.

Required Parameters

execute_onLINEARThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM.
Default:LINEAR
C++ Type:ExecFlagEnum
Options:NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM
Controllable:No
Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM.
period_time1.79769e+308The period for repetition of the base function in time
Default:1.79769e+308
C++ Type:double
Controllable:No
Description:The period for repetition of the base function in time
period_x1.79769e+308The period for repetition of the base function in the x direction
Default:1.79769e+308
C++ Type:double
Controllable:No
Description:The period for repetition of the base function in the x direction
period_y1.79769e+308The period for repetition of the base function in the y direction
Default:1.79769e+308
C++ Type:double
Controllable:No
Description:The period for repetition of the base function in the y direction
period_z1.79769e+308The period for repetition of the base function in the y direction
Default:1.79769e+308
C++ Type:double
Controllable:No
Description:The period for repetition of the base function in the y direction

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Controllable:No
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:No
Description:Set the enabled status of the MooseObject.

Advanced Parameters

(moose/test/tests/functions/periodic_function/periodic_function.i)

[Mesh]
  type = GeneratedMesh
  dim = 3
  #Offsets of 0.1 are intentionally used to avoid test stability issues that could
  #arise from evaluating the functions directly on discontinuities.
  xmin = -1.9
  xmax =  2.1
  ymin = -1.9
  ymax =  2.1
  zmin = -1.9
  zmax =  2.1
  nx = 12
  ny = 12
  nz = 12
  elem_type = HEX8
[]

[Functions]
  [base_t]
    type = ParsedFunction
    expression = 't'
  []
  [periodic_t]
    type = PeriodicFunction
    base_function = base_t
    period_time = 1
  []
  [base_x]
    type = ParsedFunction
    expression = 'x'
  []
  [periodic_x]
    type = PeriodicFunction
    base_function = base_x
    period_x = 1
  []
  [base_y]
    type = ParsedFunction
    expression = 'y'
  []
  [periodic_y]
    type = PeriodicFunction
    base_function = base_y
    period_y = 1
  []
  [base_z]
    type = ParsedFunction
    expression = 'z'
  []
  [periodic_z]
    type = PeriodicFunction
    base_function = base_z
    period_z = 1
  []
  [base_xyzt]
    type = ParsedFunction
    expression = 'x+y+z+t'
  []
  [periodic_xyzt]
    type = PeriodicFunction
    base_function = base_xyzt
    period_x = 1
    period_y = 1
    period_z = 1
    period_time = 1
  []
[]

[AuxVariables]
  [pt]
  []
  [px]
  []
  [py]
  []
  [pz]
  []
  [pxyzt]
  []
[]

[AuxKernels]
  [pt]
    type = FunctionAux
    variable = pt
    function = periodic_t
    execute_on = 'initial timestep_end'
  []
  [px]
    type = FunctionAux
    variable = px
    function = periodic_x
    execute_on = 'initial timestep_end'
  []
  [py]
    type = FunctionAux
    variable = py
    function = periodic_y
    execute_on = 'initial timestep_end'
  []
  [pz]
    type = FunctionAux
    variable = pz
    function = periodic_z
    execute_on = 'initial timestep_end'
  []
  [pxyzt]
    type = FunctionAux
    variable = pxyzt
    function = periodic_xyzt
    execute_on = 'initial timestep_end'
  []
[]

[Problem]
  solve = false
[]

[Executioner]
  type = Transient

  #Offsets of 0.1 are intentionally used to avoid test stability issues that could
  #arise from evaluating the functions directly on discontinuities.
  start_time = -1.9
  end_time = 2.1
  dt = 0.5
[]

[Outputs]
  exodus = true
[]