DirectionalNeumannBC

Imposes the integrated boundary condition $var element = document.getElementById("moose-equation-fc73e7c8-2c80-4aee-8063-57023130d392");katex.render("\\frac{\\partial u}{\\partial n}=\\vec{V}\\cdot\\hat{n}", element, {displayMode:false,throwOnError:false});$ , where $var element = document.getElementById("moose-equation-75d9d251-95e4-4cbd-a8d8-128920e25088");katex.render("\\vec{V}", element, {displayMode:false,throwOnError:false});$ is a user-defined, constant vector.

Description

DirectionalNeumannBC is an IntegratedBC which weakly imposes the flux boundary condition $var element = document.getElementById("moose-equation-c15240a6-dbea-4834-9c29-ecc6319875e8");katex.render("\\frac{\\partial u}{\\partial n} = \\vec{V}\\cdot\\hat{n}", element, {displayMode:false,throwOnError:false});$ , where the user specifies the vector $var element = document.getElementById("moose-equation-f2921bdd-716b-476d-87fd-a1adcb7691ba");katex.render("\\vec{V}", element, {displayMode:false,throwOnError:false});$ and the unit normal vector $var element = document.getElementById("moose-equation-874e456b-62ef-472b-943b-a24c8df7afef");katex.render("\\hat{n}", element, {displayMode:false,throwOnError:false});$ is determined by the geometry of the domain $var element = document.getElementById("moose-equation-4cb63426-aad4-44ae-acaf-d9492a9fb182");katex.render("\\Omega", element, {displayMode:false,throwOnError:false});$ . This class is appropriate to use in systems of partial differential equations (PDEs) of the form $var element = document.getElementById("moose-equation-6da0b93f-a313-4835-b1cf-1d75624715e3");katex.render("\\begin{aligned} -\\nabla^2 u &= f && \\quad \\in \\Omega \\\\ u &= g && \\quad \\in \\partial \\Omega_D \\\\ \\frac{\\partial u}{\\partial n} &= \\vec{V} \\cdot \\hat{n} && \\quad \\in \\partial \\Omega_N \\end{aligned}", element, {displayMode:true,throwOnError:false});$

note

There is not a 1:1 correspondence between the choice of $var element = document.getElementById("moose-equation-96e3b0d0-56b2-49ee-9ed0-6e03403c63e6");katex.render("\\vec{V}", element, {displayMode:false,throwOnError:false});$ and the resulting solution, since the component of $var element = document.getElementById("moose-equation-4186d70f-b6f6-4479-92ab-0b9c957f908a");katex.render("\\vec{V}", element, {displayMode:false,throwOnError:false});$ which is orthogonal to the outward normal vector will not have any effect on the result.

This class exists mainly for convenience: if the true solution has a constant flux, then it is easier to specify Neumann boundary conditions on parts of the boundary with different outward normal vectors by simply specifying the true constant flux vector, and allowing MOOSE to dot it with the appropriate outward normals as necessary.

Example Input Syntax

  [./top]
    type = VectorNeumannBC
    variable = u
    vector_value = '1 1 0'
    boundary = 2
  [../]

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
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

displacementsThe displacements
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:The displacements
prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Unit:(no unit assumed)
Controllable:No
Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
use_interpolated_stateFalseFor the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
Default:False
C++ Type:bool
Unit:(no unit assumed)
Controllable:No
Description:For the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
vector_value0 0 0vector this BC should act in
Default:0 0 0
C++ Type:libMesh::VectorValue<double>
Unit:(no unit assumed)
Controllable:No
Description:vector this BC should act in

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_tagssystemThe tag for the matrices this Kernel should fill
Default:system
C++ Type:MultiMooseEnum
Unit:(no unit assumed)
Options:nontime, system
Controllable:No
Description:The tag for the matrices this Kernel should fill
vector_tagsnontimeThe tag for the vectors this Kernel should fill
Default:nontime
C++ Type:MultiMooseEnum
Unit:(no unit assumed)
Options:nontime, time
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.
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.)
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
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.)
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/misc_bcs/vector_neumann_bc_test.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  nz = 0
  zmin = 0
  zmax = 0
  elem_type = QUAD4
[]

[Variables]
  active = 'u'

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

[Kernels]
  active = 'diff'

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

[BCs]
  active = 'left right top'

  [./left]
    type = DirichletBC
    variable = u
    boundary = 3
    value = 0.0
  [../]

  [./right]
    type = DirichletBC
    variable = u
    boundary = 1
    value = 2.0
  [../]

  [./top]
    type = VectorNeumannBC
    variable = u
    vector_value = '1 1 0'
    boundary = 2
  [../]
[]

[Executioner]
  type = Steady

  solve_type = 'PJFNK'
[]

[Outputs]
  exodus = true
[]

Description
Example Input Syntax
Input Parameters