FunctionDirichletBC

Imposes the essential boundary condition , where is a (possibly) time and space-dependent MOOSE Function.

Description

FunctionDirichletBC is a generalization of DirichletBC which imposes a possibly temporally- and spatially-dependent value defined by a MOOSE Function object on a particular set of degrees of freedom (DOFs) defined by the boundary parameter. That is, for a PDE of the form

where is the domain, and is its boundary, a FunctionDirichletBC object can be used to impose the condition (2) if the function is well-defined for . In this case, the function parameter corresponds to a MOOSE Function object which represents the mathematical function , and the user must define one or more sidesets corresponding to the boundary subset via the boundary parameter.

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 = FunctionDirichletBC
    variable = u
    boundary = 'left right'
    function = bc_func
  [../]
[]
(../moose/test/tests/bcs/function_dirichlet_bc/test.i)

Input Parameters

  • boundaryThe list of boundary IDs from the mesh where this object applies

    C++ Type:std::vector<BoundaryName>

    Controllable:No

    Description:The list of boundary IDs from the mesh where this object applies

  • functionThe forcing function.

    C++ Type:FunctionName

    Controllable:No

    Description:The forcing function.

  • variableThe name of the variable that this residual object operates on

    C++ Type:NonlinearVariableName

    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>

    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>

    Controllable:No

    Description:The displacements

  • presetTrueWhether or not to preset the BC (apply the value before the solve begins).

    Default:True

    C++ Type:bool

    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>

    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>

    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>

    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>

    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

    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

    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>

    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

    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

    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

    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

    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