XFEMEqualValueAtInterface

enforce a same value on both sides of the interface.

Description

The XFEMEqualValueAtInterface enforces $var element = document.getElementById("moose-equation-2f289add-ceb3-4913-83b4-1497cc448c75");katex.render("u_{\\Gamma^+} = u_{\\Gamma^-}= a", element, {macros:{"\\pf":"\\frac{\\partial #1}{\\partial #2}"},throwOnError:false,displayMode:false});$ at the interface using a penalty approach.

Example Input File Syntax

[./xfem_constraint]
  type = XFEMEqualValueAtInterface
  geometric_cut_userobject = 'line_seg_cut_uo'
  use_displaced_mesh = false
  variable = u
  value = 1
  alpha = 1e5
[../]

/opt/civet/build_0/moose/modules/xfem/test/tests/single_var_constraint_2d/equal_value.i

[GlobalParams]
  order = FIRST
  family = LAGRANGE
[]

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 5
  ny = 1
  xmin = 0.0
  xmax = 1.0
  ymin = 0.0
  ymax = 1.0
  elem_type = QUAD4
[]

[XFEM]
  qrule = volfrac
  output_cut_plane = true
[]

[UserObjects]
  [./line_seg_cut_uo]
    type = LineSegmentCutUserObject
    cut_data = '0.5 1.0 0.5 0.0'
  [../]
[]

[Variables]
  [./u]
  [../]
[]

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

[Constraints]
  [./xfem_constraint]
    type = XFEMEqualValueAtInterface
    geometric_cut_userobject = 'line_seg_cut_uo'
    use_displaced_mesh = false
    variable = u
    value = 1
    alpha = 1e5
  [../]
[]

[BCs]
# Define boundary conditions
  [./left_u]
    type = DirichletBC
    variable = u
    boundary = 3
    value = 1
  [../]

  [./right_u]
    type = DirichletBC
    variable = u
    boundary = 1
    value = 0
  [../]
[]

[Executioner]
  type = Steady
  solve_type = 'PJFNK'
  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
  line_search = 'none'

  l_tol = 1e-3
  nl_max_its = 15
  nl_rel_tol = 1e-10
  nl_abs_tol = 1e-10
[]

[Outputs]
  interval = 1
  execute_on = timestep_end
  exodus = true
  perf_graph = true
  [./console]
    type = Console
    output_linear = true
  [../]
[]

Input Parameters

variableThe name of the variable that this constraint is applied to.
C++ Type:NonlinearVariableName
Options:
Description:The name of the variable that this constraint is applied to.
alphaPenalty parameter in penalty formulation.
C++ Type:double
Options:
Description:Penalty parameter in penalty formulation.
valuePrescribed value at the interface.
C++ Type:double
Options:
Description:Prescribed value at the interface.

Required Parameters

geometric_cut_userobjectName of GeometricCutUserObject associated with this constraint.
C++ Type:UserObjectName
Options:
Description:Name of GeometricCutUserObject associated with this constraint.
execute_onLINEARThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.
Default:LINEAR
C++ Type:ExecFlagEnum
Options:NONE INITIAL LINEAR NONLINEAR TIMESTEP_END TIMESTEP_BEGIN FINAL CUSTOM
Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.
interface_id0The id of the interface.
Default:0
C++ Type:unsigned int
Options:
Description:The id of the interface.

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
Description:Set the enabled status of the MooseObject.
use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
Default:False
C++ Type:bool
Options:
Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Advanced Parameters

Input Files

modules/xfem/test/tests/moving_interface/phase_transition.i
modules/xfem/test/tests/single_var_constraint_2d/equal_value.i

modules/xfem/test/tests/moving_interface/phase_transition.i

[GlobalParams]
  order = FIRST
  family = LAGRANGE
[]

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 11
  ny = 1
  xmin = 0
  xmax = 2
  ymin = 0
  ymax = 1
  elem_type = QUAD4
[]

[XFEM]
  qrule = volfrac
  output_cut_plane = true
[]

[UserObjects]
  [./velocity]
    type = XFEMPhaseTransitionMovingInterfaceVelocity
    diffusivity_at_positive_level_set = 5
    diffusivity_at_negative_level_set = 1
    equilibrium_concentration_jump = 1
    value_at_interface_uo = value_uo
  [../]
  [./value_uo]
    type = PointValueAtXFEMInterface
    variable = 'u'
    geometric_cut_userobject = 'moving_line_segments'
    execute_on = 'nonlinear'
    level_set_var = ls
  [../]
  [./moving_line_segments]
    type = MovingLineSegmentCutSetUserObject
    cut_data = '0.5 0 0.5 1.0 0 0'
    heal_always = true
    interface_velocity = velocity
  [../]
[]

[Variables]
  [./u]
  [../]
[]

[ICs]
  [./ic_u]
    type = FunctionIC
    variable = u
    function = 'if(x<0.51, 2, 1)'
  [../]
[]

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

[Constraints]
  [./u_constraint]
    type = XFEMEqualValueAtInterface
    geometric_cut_userobject = 'moving_line_segments'
    use_displaced_mesh = false
    variable = u
    value = 2
    alpha = 1e5
  [../]
[]

[Kernels]
  [./diff]
    type = MatDiffusion
    variable = u
    D_name = 'diffusion_coefficient'
  [../]
  [./time]
    type = TimeDerivative
    variable = u
  [../]
[]

[AuxKernels]
  [./ls]
    type = LineSegmentLevelSetAux
    line_segment_cut_set_user_object = 'moving_line_segments'
    variable = ls
  [../]
[]

[Materials]
  [./diffusivity_A]
    type = GenericConstantMaterial
    prop_names = A_diffusion_coefficient
    prop_values = 5
  [../]
  [./diffusivity_B]
    type = GenericConstantMaterial
    prop_names = B_diffusion_coefficient
    prop_values = 1
  [../]
  [./diff_combined]
    type = LevelSetBiMaterialReal
    levelset_positive_base = 'A'
    levelset_negative_base = 'B'
    level_set_var = ls
    prop_name = diffusion_coefficient
  [../]
[]

[BCs]
# Define boundary conditions
  [./left_u]
    type = DirichletBC
    variable = u
    value = 2
    boundary = 3
  [../]

  [./right_u]
    type = NeumannBC
    variable = u
    boundary = 1
    value = 0
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'PJFNK'
  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
  line_search = 'none'

  l_tol = 1e-3
  nl_max_its = 15
  nl_rel_tol = 1e-12
  nl_abs_tol = 1e-11

  start_time = 0.0
  dt = 0.01
  num_steps = 4
  max_xfem_update = 1
[]


[Outputs]
  execute_on = timestep_end
  exodus = true
  perf_graph = true
  [./console]
    type = Console
    output_linear = true
  [../]
  csv = true
[]

modules/xfem/test/tests/single_var_constraint_2d/equal_value.i

[GlobalParams]
  order = FIRST
  family = LAGRANGE
[]

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 5
  ny = 1
  xmin = 0.0
  xmax = 1.0
  ymin = 0.0
  ymax = 1.0
  elem_type = QUAD4
[]

[XFEM]
  qrule = volfrac
  output_cut_plane = true
[]

[UserObjects]
  [./line_seg_cut_uo]
    type = LineSegmentCutUserObject
    cut_data = '0.5 1.0 0.5 0.0'
  [../]
[]

[Variables]
  [./u]
  [../]
[]

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

[Constraints]
  [./xfem_constraint]
    type = XFEMEqualValueAtInterface
    geometric_cut_userobject = 'line_seg_cut_uo'
    use_displaced_mesh = false
    variable = u
    value = 1
    alpha = 1e5
  [../]
[]

[BCs]
# Define boundary conditions
  [./left_u]
    type = DirichletBC
    variable = u
    boundary = 3
    value = 1
  [../]

  [./right_u]
    type = DirichletBC
    variable = u
    boundary = 1
    value = 0
  [../]
[]

[Executioner]
  type = Steady
  solve_type = 'PJFNK'
  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
  line_search = 'none'

  l_tol = 1e-3
  nl_max_its = 15
  nl_rel_tol = 1e-10
  nl_abs_tol = 1e-10
[]

[Outputs]
  interval = 1
  execute_on = timestep_end
  exodus = true
  perf_graph = true
  [./console]
    type = Console
    output_linear = true
  [../]
[]

References

Description
Example Input File Syntax
Input Parameters
Input Files
References

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