TimeDerivativeAux

Returns the time derivative of the specified variable/functor as an auxiliary variable.

The "factor" multiplies the output of the time derivative operation. The time derivative of the "factor" is not computed.

warning

The TimeDerivativeAux is restricted to constructs for which the time derivative is computed by MOOSE. Time derivative functions have not been implemented for all functor types.

Example input syntax

In this example, the TimeDerivativeAux is used to output to auxiliary variables the time derivatives of variables and functions during a time dependent diffusion problem.

[AuxKernels<<<{"href": "../../syntax/AuxKernels/index.html"}>>>]
  # Time derivative of a nonlinear variable
  [var_derivative]
    type = TimeDerivativeAux<<<{"description": "Returns the time derivative of the specified variable/functor as an auxiliary variable.", "href": "TimeDerivativeAux.html"}>>>
    variable<<<{"description": "The name of the variable that this object applies to"}>>> = variable_derivative
    functor<<<{"description": "Functor to take the time derivative of. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number."}>>> = u
    factor<<<{"description": "Factor to multiply the time derivative by. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number."}>>> = 10
    execute_on<<<{"description": "The list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html."}>>> = 'TIMESTEP_END'
  []
  # this places the derivative of a FE variable in a FV one
  # let's output a warning
  inactive<<<{"description": "If specified blocks matching these identifiers will be skipped."}>>> = 'var_derivative_to_fv'
  [var_derivative_to_fv]
    type = TimeDerivativeAux<<<{"description": "Returns the time derivative of the specified variable/functor as an auxiliary variable.", "href": "TimeDerivativeAux.html"}>>>
    variable<<<{"description": "The name of the variable that this object applies to"}>>> = variable_derivative_fv
    functor<<<{"description": "Functor to take the time derivative of. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number."}>>> = u
  []

  # Time derivative of a function: using the functor system
  # Time derivative of a functor material property is not currently supported
  [function_derivative_quadrature_point]
    type = TimeDerivativeAux<<<{"description": "Returns the time derivative of the specified variable/functor as an auxiliary variable.", "href": "TimeDerivativeAux.html"}>>>
    variable<<<{"description": "The name of the variable that this object applies to"}>>> = function_derivative_qp
    functor<<<{"description": "Functor to take the time derivative of. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number."}>>> = 'some_function'
    factor<<<{"description": "Factor to multiply the time derivative by. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number."}>>> = 2
    execute_on<<<{"description": "The list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html."}>>> = 'INITIAL TIMESTEP_END'
  []
  [function_derivative_element]
    type = TimeDerivativeAux<<<{"description": "Returns the time derivative of the specified variable/functor as an auxiliary variable.", "href": "TimeDerivativeAux.html"}>>>
    variable<<<{"description": "The name of the variable that this object applies to"}>>> = function_derivative_elem
    functor<<<{"description": "Functor to take the time derivative of. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number."}>>> = 'some_other_function'
    factor<<<{"description": "Factor to multiply the time derivative by. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number."}>>> = 2
    execute_on<<<{"description": "The list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html."}>>> = 'INITIAL TIMESTEP_END'
  []
[]

[AuxVariables<<<{"href": "../../syntax/AuxVariables/index.html"}>>>]
  [variable_derivative]
    family<<<{"description": "Specifies the family of FE shape functions to use for this variable"}>>> = MONOMIAL
    order<<<{"description": "Specifies the order of the FE shape function to use for this variable (additional orders not listed are allowed)"}>>> = CONSTANT
  []
  inactive<<<{"description": "If specified blocks matching these identifiers will be skipped."}>>> = 'variable_derivative_fv'
  [variable_derivative_fv]
    family<<<{"description": "Specifies the family of FE shape functions to use for this variable"}>>> = MONOMIAL
    order<<<{"description": "Specifies the order of the FE shape function to use for this variable (additional orders not listed are allowed)"}>>> = CONSTANT
    fv = true
  []
  [function_derivative_qp]
    family<<<{"description": "Specifies the family of FE shape functions to use for this variable"}>>> = MONOMIAL
    order<<<{"description": "Specifies the order of the FE shape function to use for this variable (additional orders not listed are allowed)"}>>> = FIRST
  []
  [function_derivative_elem]
    family<<<{"description": "Specifies the family of FE shape functions to use for this variable"}>>> = MONOMIAL
    order<<<{"description": "Specifies the order of the FE shape function to use for this variable (additional orders not listed are allowed)"}>>> = CONSTANT
  []
[]

[Functions<<<{"href": "../../syntax/Functions/index.html"}>>>]
  # These functions have implemented time derivatives
  [some_function]
    type = ParsedFunction<<<{"description": "Function created by parsing a string", "href": "../functions/MooseParsedFunction.html"}>>>
    expression<<<{"description": "The user defined function."}>>> = t*(x+y)
  []
  [some_other_function]
    type = PiecewiseLinear<<<{"description": "Linearly interpolates between pairs of x-y data", "href": "../functions/PiecewiseLinear.html"}>>>
    x<<<{"description": "The abscissa values"}>>> = '0 0.05 0.15 0.25'
    y<<<{"description": "The ordinate values"}>>> = '1 2 3 4'
  []
[]

Input Parameters

variableThe name of the variable that this object applies to
C++ Type:AuxVariableName
Unit:(no unit assumed)
Controllable:No
Description:The name of the variable that this object applies to

Required Parameters

blockThe list of blocks (ids or names) that this object will be applied
C++ Type:std::vector<SubdomainName>
Controllable:No
Description:The list of blocks (ids or names) that this object will be applied
boundaryThe list of boundaries (ids or names) from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundaries (ids or names) from the mesh where this object applies
check_boundary_restrictedTrueWhether to check for multiple element sides on the boundary in the case of a boundary restricted, element aux variable. Setting this to false will allow contribution to a single element's elemental value(s) from multiple boundary sides on the same element (example: when the restricted boundary exists on two or more sides of an element, such as at a corner of a mesh
Default:True
C++ Type:bool
Controllable:No
Description:Whether to check for multiple element sides on the boundary in the case of a boundary restricted, element aux variable. Setting this to false will allow contribution to a single element's elemental value(s) from multiple boundary sides on the same element (example: when the restricted boundary exists on two or more sides of an element, such as at a corner of a mesh
execute_onLINEAR TIMESTEP_ENDThe list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html.
Default:LINEAR TIMESTEP_END
C++ Type:ExecFlagEnum
Options:NONE, INITIAL, LINEAR, NONLINEAR_CONVERGENCE, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, PRE_DISPLACE
Controllable:No
Description:The list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html.
factor1Factor to multiply the time derivative by. 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:Factor to multiply the time derivative by. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number.
functorFunctor to take the time derivative of. 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:Functor to take the time derivative of. A functor is any of the following: a variable, a functor material property, a function, a post-processor, or a number.

Optional 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.
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

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
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.

Material Property Retrieval Parameters

(moose/test/tests/auxkernels/time_derivative_aux/test.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  xmin = 0
  xmax = 1
  ymin = 0
  ymax = 1
  nx = 3
  ny = 2
[]

[Functions]
  # These functions have implemented time derivatives
  [some_function]
    type = ParsedFunction
    expression = t*(x+y)
  []
  [some_other_function]
    type = PiecewiseLinear
    x = '0 0.05 0.15 0.25'
    y = '1 2 3 4'
  []
[]

[Variables]
  [u]
  []
[]

[Kernels]
  [time]
    type = TimeDerivative
    variable = u
  []
  [reaction]
    type = Reaction
    variable = u
  []
  [diffusion]
    type = Diffusion
    variable = u
  []
[]

[BCs]
  [left]
    type = NeumannBC
    variable = u
    value = 5
    boundary = 'left'
  []
[]

[Materials]
  [material]
    type = GenericFunctorMaterial
    prop_names = 'some_matprop'
    prop_values = 'some_function'
  []
[]

[AuxVariables]
  [variable_derivative]
    family = MONOMIAL
    order = CONSTANT
  []
  inactive = 'variable_derivative_fv'
  [variable_derivative_fv]
    family = MONOMIAL
    order = CONSTANT
    fv = true
  []
  [function_derivative_qp]
    family = MONOMIAL
    order = FIRST
  []
  [function_derivative_elem]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  # Time derivative of a nonlinear variable
  [var_derivative]
    type = TimeDerivativeAux
    variable = variable_derivative
    functor = u
    factor = 10
    execute_on = 'TIMESTEP_END'
  []
  # this places the derivative of a FE variable in a FV one
  # let's output a warning
  inactive = 'var_derivative_to_fv'
  [var_derivative_to_fv]
    type = TimeDerivativeAux
    variable = variable_derivative_fv
    functor = u
  []

  # Time derivative of a function: using the functor system
  # Time derivative of a functor material property is not currently supported
  [function_derivative_quadrature_point]
    type = TimeDerivativeAux
    variable = function_derivative_qp
    functor = 'some_function'
    factor = 2
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [function_derivative_element]
    type = TimeDerivativeAux
    variable = function_derivative_elem
    functor = 'some_other_function'
    factor = 2
    execute_on = 'INITIAL TIMESTEP_END'
  []
[]

[Executioner]
  type = Transient
  dt = 0.1
  num_steps = 2
  nl_abs_tol = 1e-12
[]

[Outputs]
  exodus = true
[]