FunctorDirichletBC

Imposes the Dirichlet boundary condition $var element = document.getElementById("moose-equation-ea751cb5-cdd8-41ee-a34b-5439200eaf45");katex.render("u(t,\\vec{x})=h(t,\\vec{x})", element, {displayMode:false,throwOnError:false});$ , where $var element = document.getElementById("moose-equation-1ce751c8-90ed-430e-8134-eb243acc5f65");katex.render("h", element, {displayMode:false,throwOnError:false});$ is a functor and can have complex dependencies.

Description

FunctorDirichletBC is a generalization of DirichletBC which imposes a possibly temporally- and spatially-dependent, possibly coupled to other variables/functors, value defined by a MOOSE Functor object on a particular set of degrees of freedom (DOFs) defined by the boundary parameter. That is, for a PDE of the form

$var element = document.getElementById("moose-equation-68ce04b4-826b-4f5d-a9f6-9832c67f7fcb");katex.render("\\begin{aligned} -\\nabla^2 u &= f && \\quad \\in \\Omega \\\\ u &= g(t,\\vec{x}) && \\quad \\in \\partial \\Omega_D \\\\ \\frac{\\partial u}{\\partial n} &= c(t,,\\vec{x},...) h(t,\\vec{x}, ...) && \\quad \\in \\partial \\Omega_N \\end{aligned}", element, {displayMode:true,throwOnError:false});$

where $var element = document.getElementById("moose-equation-c6590122-da32-42bd-b39c-e91c9cce1c9e");katex.render("\\Omega \\subset \\mathbb{R}^n", element, {displayMode:false,throwOnError:false});$ is the domain, and $var element = document.getElementById("moose-equation-261b513a-a0f4-4389-85ac-a911adc271d9");katex.render("\\partial \\Omega = \\partial \\Omega_D \\cup \\partial \\Omega_N", element, {displayMode:false,throwOnError:false});$ is its boundary, a FunctorDirichletBC object can be used to impose the condition (2) if the Functor is well-defined for $var element = document.getElementById("moose-equation-2d408e8e-2ad9-4dff-9d1d-45ce01f5025a");katex.render("\\vec{x} \\in \\partial \\Omega_D", element, {displayMode:false,throwOnError:false});$ . In this case, the "functor" parameter corresponds to a MOOSE Functor object and h in the equation for the boundary condition. Similarly c corresponds to a functor "coefficient" parameter. Both the functor and the coefficient can have arbitrary dependencies on other functors, which can include variables, functions, postprocessors, etc.

The user must define one or more sidesets corresponding to the boundary subset $var element = document.getElementById("moose-equation-cddef002-d761-42d7-b19c-0bcf6dad8eff");katex.render("\\partial \\Omega_D", element, {displayMode:false,throwOnError:false});$ via the boundary parameter and it is the user's responsibility to ensure the functor and the coefficient are defined there.

Preset boundary conditions

With the parameter preset = true, the value of the boundary condition is applied before the solve begins. With preset = false, the boundary condition is only enforced as the solve progresses. In most situations, presetting the boundary condition is better.

Example Input Syntax

[BCs]
  [all]
    type = FunctorDirichletBC
    variable = u
    boundary = 'left right'
    functor = bc_func
  []
[]

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
functorThe functor to impose. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:The functor to impose. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number.
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

coefficient1An optional functor coefficient to multiply the imposed functor. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number.
Default:1
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:An optional functor coefficient to multiply the imposed functor. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number.
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
presetTrueWhether or not to preset the BC (apply the value before the solve begins).
Default:True
C++ Type:bool
Unit:(no unit assumed)
Controllable:No
Description:Whether or not to preset the BC (apply the value before the solve begins).
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.)

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/functor_dirichlet_bc/test.i)

[Mesh]
  [square]
    type = GeneratedMeshGenerator
    dim = 2
    nx = 32
    ny = 32
  []
[]

[Variables]
  [u]
  []
[]

[Functions]
  [ff_1]
    type = ParsedFunction
    expression = alpha*alpha*pi
    symbol_names = 'alpha'
    symbol_values = '16'
  []

  [ff_2]
    type = ParsedFunction
    expression = pi*sin(alpha*pi*x)
    symbol_names = 'alpha'
    symbol_values = '16'
  []

  [forcing_func]
    type = CompositeFunction
    functions = 'ff_1 ff_2'
  []

  [bc_func]
    type = ParsedFunction
    expression = sin(alpha*pi*x)
    symbol_names = 'alpha'
    symbol_values = '16'
  []
[]

[Kernels]
  [diff]
    type = Diffusion
    variable = u
  []
  [forcing]
    type = BodyForce
    variable = u
    function = forcing_func
  []
[]

[BCs]
  [all]
    type = FunctorDirichletBC
    variable = u
    boundary = 'left right'
    functor = bc_func
  []
[]

[Executioner]
  type = Steady
  nl_rel_tol = 1e-12
[]

[Outputs]
  execute_on = 'timestep_end'
  exodus = true
[]

Description
Preset boundary conditions
Example Input Syntax
Input Parameters