MatchedValueBC

Implements a NodalBC which equates two different Variables' values on a specified boundary.

Description

MatchedValueBC is a NodalBC which applies to systems of two or more variables, and can be used to impose equality of two solutions along a given boundary. This class is appropriate for systems of partial differential equations (PDEs) of the form $var element = document.getElementById("moose-equation-9498f2fb-e408-4c0d-9198-63116864f759");katex.render("\\begin{aligned} -\\nabla^2 u &= f_1 && \\quad \\in \\Omega \\\\ -\\nabla^2 v &= f_2 && \\quad \\in \\Omega \\\\ \\frac{\\partial u}{\\partial n} &= h_1 && \\quad \\in \\partial \\Omega_N \\\\ \\frac{\\partial v}{\\partial n} &= h_2 && \\quad \\in \\partial \\Omega_N \\\\ u &= v && \\quad \\in \\partial \\Omega_D, \\end{aligned}", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-749abf77-b6bb-42c5-8c55-a5e76810fbd1");katex.render("\\Omega \\subset \\mathbb{R}^n", element, {displayMode:false,throwOnError:false});$ is the domain, and $var element = document.getElementById("moose-equation-f78f21a9-2396-4436-9162-7aef0286f261");katex.render("\\partial \\Omega = \\partial \\Omega_D \\cup \\partial \\Omega_N", element, {displayMode:false,throwOnError:false});$ is its boundary, $var element = document.getElementById("moose-equation-f7d62be4-3c73-46f0-a514-f0e7274f5fa1");katex.render("u", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-f3bc5732-cff2-4a8a-b76d-c108849a2582");katex.render("v", element, {displayMode:false,throwOnError:false});$ are the unknowns, $var element = document.getElementById("moose-equation-7d21e0b3-b308-43a2-854b-6e29b62218b7");katex.render("f_1", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-91c663bf-a39f-49d6-88c2-5cbccb0177f7");katex.render("f_2", element, {displayMode:false,throwOnError:false});$ are forcing functions (which may depend on both $var element = document.getElementById("moose-equation-7312bb6b-6af4-4490-b85b-7bef55a69583");katex.render("u", element, {displayMode:false,throwOnError:false});$ and $var element = document.getElementById("moose-equation-9a126047-a015-4d13-a625-648e73057ec2");katex.render("v", element, {displayMode:false,throwOnError:false});$ ), and $var element = document.getElementById("moose-equation-f3173e95-c650-4bfb-a61e-53a8394cb897");katex.render("h_1", element, {displayMode:false,throwOnError:false});$ and $var element = document.getElementById("moose-equation-726974f6-0909-41d4-a709-a5d22385550f");katex.render("h_2", element, {displayMode:false,throwOnError:false});$ are given fluxes. The v parameter is used to specify the variable whose value is tied to $var element = document.getElementById("moose-equation-c246657e-0dbf-41ef-a4ab-a5ba5ca254f3");katex.render("u", element, {displayMode:false,throwOnError:false});$ . In the example below, the other variable's name happens to be v as well.

Example Input Syntax

  [./left_u]
    type = MatchedValueBC
    variable = u
    boundary = 3
    v = v
  [../]

Input Parameters

boundaryThe list of boundary IDs from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Unit:(no unit assumed)
Controllable:No
Description:The list of boundary IDs from the mesh where this object applies
vThe variable whose value we are to match.
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:The variable whose value we are to match.
variableThe name of the variable that this residual object operates on
C++ Type:NonlinearVariableName
Unit:(no unit assumed)
Controllable:No
Description:The name of the variable that this residual object operates on

Required Parameters

diag_save_inThe name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector<AuxVariableName>
Unit:(no unit assumed)
Controllable:No
Description:The name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
displacementsThe displacements
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:The displacements
save_inThe name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector<AuxVariableName>
Unit:(no unit assumed)
Controllable:No
Description:The name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
u_coeff1 A coefficient for primary variable u
Default:1
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description: A coefficient for primary variable u
v_coeff1 A coefficient for coupled variable v
Default:1
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description: A coefficient for coupled variable v

Optional Parameters

absolute_value_vector_tagsThe tags for the vectors this residual object should fill with the absolute value of the residual contribution
C++ Type:std::vector<TagName>
Unit:(no unit assumed)
Controllable:No
Description:The tags for the vectors this residual object should fill with the absolute value of the residual contribution
extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector<TagName>
Unit:(no unit assumed)
Controllable:No
Description:The extra tags for the matrices this Kernel should fill
extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector<TagName>
Unit:(no unit assumed)
Controllable:No
Description:The extra tags for the vectors this Kernel should fill
matrix_tagssystem timeThe tag for the matrices this Kernel should fill
Default:system time
C++ Type:MultiMooseEnum
Unit:(no unit assumed)
Options:nontime, system, time
Controllable:No
Description:The tag for the matrices this Kernel should fill
vector_tagsresidualThe tag for the vectors this Kernel should fill
Default:residual
C++ Type:MultiMooseEnum
Unit:(no unit assumed)
Options:nontime, time, residual
Controllable:No
Description:The tag for the vectors this Kernel should fill

Tagging Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Unit:(no unit assumed)
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
Unit:(no unit assumed)
Controllable:Yes
Description:Set the enabled status of the MooseObject.
implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Unit:(no unit assumed)
Controllable:No
Description:Determines whether this object is calculated using an implicit or explicit form
seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Unit:(no unit assumed)
Controllable:No
Description:The seed for the master random number generator
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
Unit:(no unit assumed)
Controllable:No
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

(moose/test/tests/bcs/matched_value_bc/matched_value_bc_test.i)

[Mesh]
  [./square]
    type = GeneratedMeshGenerator
    nx = 2
    ny = 2
    dim = 2
  [../]
[]

# Solves a pair of coupled diffusion equations where u=v on the boundary

[Variables]
  active = 'u v'

  [./u]
    order = FIRST
    family = LAGRANGE
    initial_condition = 3
  [../]

  [./v]
    order = FIRST
    family = LAGRANGE
    initial_condition = 2
  [../]
[]

[Kernels]
  active = 'diff_u diff_v'

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

  [./diff_v]
    type = Diffusion
    variable = v
  [../]
[]

[BCs]
  active = 'right_v left_u'

  [./right_v]
    type = DirichletBC
    variable = v
    boundary = 1
    value = 3
  [../]

  [./left_u]
    type = MatchedValueBC
    variable = u
    boundary = 3
    v = v
  [../]
[]

[Preconditioning]
  [./precond]
    type = SMP
    full = true
  [../]
[]

[Executioner]
  type = Steady
  solve_type = 'NEWTON'

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

  nl_rel_tol = 1e-10
  l_tol = 1e-12
[]

[Outputs]
  file_base = out
  exodus = true
[]

Description
Example Input Syntax
Input Parameters