PolycrystalRandomICAction

Overview

This action creates the initial conditions (ICs) for the op_num order parameters used to represent a polycrystal with a random initial condition.

The action creates the IC for each of the variables with PolycrystalRandomIC.

Example Input File Syntax

The PolycrystalRandomICAction is accessed through the ICs/PolycrystalICs block, as shown below.

[GlobalParams]
  # Parameters used by several kernels that are defined globally to simplify input file
  op_num = 10 # Number of grains
  var_name_base = gr # Base name of grains
[]

[ICs]
  [PolycrystalICs]
    [PolycrystalRandomIC]
      random_type = discrete
    []
  []
[]

Input Parameters

op_numnumber of order parameters to create
C++ Type:unsigned int
Controllable:No
Description:number of order parameters to create
random_typeThe type of random polycrystal initial condition. Whether one order parameter is chosen to be 1 at each node or if each other parameter continuously varies from 0 to 1
C++ Type:MooseEnum
Options:continuous, discrete
Controllable:No
Description:The type of random polycrystal initial condition. Whether one order parameter is chosen to be 1 at each node or if each other parameter continuously varies from 0 to 1
var_name_basespecifies the base name of the variables
C++ Type:std::string
Controllable:No
Description:specifies the base name of the variables

Required Parameters

active__all__ If specified only the blocks named will be visited and made active
Default:__all__
C++ Type:std::vector<std::string>
Controllable:No
Description:If specified only the blocks named will be visited and made active
blockBlock restriction for the initial condition
C++ Type:std::vector<SubdomainName>
Controllable:No
Description:Block restriction for the initial condition
inactiveIf specified blocks matching these identifiers will be skipped.
C++ Type:std::vector<std::string>
Controllable:No
Description:If specified blocks matching these identifiers will be skipped.

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.

Advanced Parameters

(moose/modules/phase_field/examples/grain_growth/grain_growth_2D_random.i)

# This initializes a polycrystal from random seeds at each node
# Mesh adaptivity and time step adaptivity are used
# Grain tracker is started once the grain structure is established

[Mesh]
  # Mesh block.  Meshes can be read in or automatically generated
  type = GeneratedMesh
  dim = 2 # Problem dimension
  nx = 40 # Number of elements in the x-direction
  ny = 40 # Number of elements in the y-direction
  xmax = 1000 # maximum x-coordinate of the mesh
  ymax = 1000 # maximum y-coordinate of the mesh
  elem_type = QUAD4 # Type of elements used in the mesh
  uniform_refine = 2 # Initial uniform refinement of the mesh

  parallel_type = replicated # Periodic BCs
[]

[GlobalParams]
  # Parameters used by several kernels that are defined globally to simplify input file
  op_num = 10 # Number of grains
  var_name_base = gr # Base name of grains
[]

[Modules]
  [PhaseField]
    [GrainGrowth]
    []
  []
[]

[ICs]
  [PolycrystalICs]
    [PolycrystalRandomIC]
      random_type = discrete
    []
  []
[]

[AuxVariables]
  # Dependent variables
  [unique_grains]
    order = CONSTANT
    family = MONOMIAL
  []
  [var_indices]
    order = CONSTANT
    family = MONOMIAL
  []
[]

[AuxKernels]
  # AuxKernel block, defining the equations used to calculate the auxvars
  [unique_grains]
    type = FeatureFloodCountAux
    variable = unique_grains
    flood_counter = grain_tracker
    field_display = UNIQUE_REGION
    execute_on = 'initial timestep_end'
  []
  [var_indices]
    type = FeatureFloodCountAux
    variable = var_indices
    flood_counter = grain_tracker
    field_display = VARIABLE_COLORING
    execute_on = 'initial timestep_end'
  []
[]

[BCs]
  # Boundary Condition block
  [Periodic]
    [top_bottom]
      auto_direction = 'x y' # Makes problem periodic in the x and y directions
    []
  []
[]

[Materials]
  [CuGrGr]
    # Material properties
    type = GBEvolution # Quantitative material properties for copper grain growth.  Dimensions are nm and ns
    GBmob0 = 2.5e-6 # Mobility prefactor for Cu from schonfelder1997molecular bibtex entry
    GBenergy = 0.708 # GB energy for Cu from schonfelder1997molecular bibtex entry
    Q = 0.23 # Activation energy for grain growth from Schonfelder 1997
    T = 450 # Constant temperature of the simulation (for mobility calculation)
    wGB = 14 # Width of the diffuse GB
  []
[]

[UserObjects]
  [grain_tracker]
    type = GrainTracker
    tracking_step = 20 #Tracking is delayed until the polycrystalline structure is established
  []
[]

[Postprocessors]
  # Scalar postprocessors
  [dt]
    # Outputs the current time step
    type = TimestepSize
  []
  [num_nodes]
    type = NumNodes
  []
[]

[Executioner]
  type = Transient # Type of executioner, here it is transient with an adaptive time step
  scheme = bdf2 # Type of time integration (2nd order backward euler), defaults to 1st order backward euler

  solve_type = PJFNK

  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre    boomeramg'

  l_max_its = 20 # Max number of linear iterations
  l_tol = 1e-4 # Relative tolerance for linear solves

  start_time = 0.0
  end_time = 4000

  [TimeStepper]
    type = IterationAdaptiveDT
    dt = 1 # Initial time step.  In this simulation it changes.
    optimal_iterations = 6 # Time step will adapt to maintain this number of nonlinear iterations
  []

  [Adaptivity]
    # Block that turns on mesh adaptivity. Note that mesh will never coarsen beyond initial mesh (before uniform refinement)
    refine_fraction = 0.8 # Fraction of high error that will be refined
    coarsen_fraction = 0.05 # Fraction of low error that will coarsened
    max_h_level = 2 # Max number of refinements used, starting from initial mesh (before uniform refinement)
  []
[]

[Outputs]
  exodus = true
  csv = true
[]

(moose/modules/phase_field/examples/grain_growth/grain_growth_2D_random.i)

# This initializes a polycrystal from random seeds at each node
# Mesh adaptivity and time step adaptivity are used
# Grain tracker is started once the grain structure is established

[Mesh]
  # Mesh block.  Meshes can be read in or automatically generated
  type = GeneratedMesh
  dim = 2 # Problem dimension
  nx = 40 # Number of elements in the x-direction
  ny = 40 # Number of elements in the y-direction
  xmax = 1000 # maximum x-coordinate of the mesh
  ymax = 1000 # maximum y-coordinate of the mesh
  elem_type = QUAD4 # Type of elements used in the mesh
  uniform_refine = 2 # Initial uniform refinement of the mesh

  parallel_type = replicated # Periodic BCs
[]

[GlobalParams]
  # Parameters used by several kernels that are defined globally to simplify input file
  op_num = 10 # Number of grains
  var_name_base = gr # Base name of grains
[]

[Modules]
  [PhaseField]
    [GrainGrowth]
    []
  []
[]

[ICs]
  [PolycrystalICs]
    [PolycrystalRandomIC]
      random_type = discrete
    []
  []
[]

[AuxVariables]
  # Dependent variables
  [unique_grains]
    order = CONSTANT
    family = MONOMIAL
  []
  [var_indices]
    order = CONSTANT
    family = MONOMIAL
  []
[]

[AuxKernels]
  # AuxKernel block, defining the equations used to calculate the auxvars
  [unique_grains]
    type = FeatureFloodCountAux
    variable = unique_grains
    flood_counter = grain_tracker
    field_display = UNIQUE_REGION
    execute_on = 'initial timestep_end'
  []
  [var_indices]
    type = FeatureFloodCountAux
    variable = var_indices
    flood_counter = grain_tracker
    field_display = VARIABLE_COLORING
    execute_on = 'initial timestep_end'
  []
[]

[BCs]
  # Boundary Condition block
  [Periodic]
    [top_bottom]
      auto_direction = 'x y' # Makes problem periodic in the x and y directions
    []
  []
[]

[Materials]
  [CuGrGr]
    # Material properties
    type = GBEvolution # Quantitative material properties for copper grain growth.  Dimensions are nm and ns
    GBmob0 = 2.5e-6 # Mobility prefactor for Cu from schonfelder1997molecular bibtex entry
    GBenergy = 0.708 # GB energy for Cu from schonfelder1997molecular bibtex entry
    Q = 0.23 # Activation energy for grain growth from Schonfelder 1997
    T = 450 # Constant temperature of the simulation (for mobility calculation)
    wGB = 14 # Width of the diffuse GB
  []
[]

[UserObjects]
  [grain_tracker]
    type = GrainTracker
    tracking_step = 20 #Tracking is delayed until the polycrystalline structure is established
  []
[]

[Postprocessors]
  # Scalar postprocessors
  [dt]
    # Outputs the current time step
    type = TimestepSize
  []
  [num_nodes]
    type = NumNodes
  []
[]

[Executioner]
  type = Transient # Type of executioner, here it is transient with an adaptive time step
  scheme = bdf2 # Type of time integration (2nd order backward euler), defaults to 1st order backward euler

  solve_type = PJFNK

  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre    boomeramg'

  l_max_its = 20 # Max number of linear iterations
  l_tol = 1e-4 # Relative tolerance for linear solves

  start_time = 0.0
  end_time = 4000

  [TimeStepper]
    type = IterationAdaptiveDT
    dt = 1 # Initial time step.  In this simulation it changes.
    optimal_iterations = 6 # Time step will adapt to maintain this number of nonlinear iterations
  []

  [Adaptivity]
    # Block that turns on mesh adaptivity. Note that mesh will never coarsen beyond initial mesh (before uniform refinement)
    refine_fraction = 0.8 # Fraction of high error that will be refined
    coarsen_fraction = 0.05 # Fraction of low error that will coarsened
    max_h_level = 2 # Max number of refinements used, starting from initial mesh (before uniform refinement)
  []
[]

[Outputs]
  exodus = true
  csv = true
[]