VariableTimeIntegrationAux

Integrates a field variable in time.

The integration over time is lead over every quadrature point.

Example syntax

In this example, the VariableTimeIntegrationAux computes the time integral of variable u with a first, second and third order scheme respectively.

[AuxKernels]
  [./MidpointTimeIntegrator]
    type = VariableTimeIntegrationAux
    variable_to_integrate = u
    variable = v_midpoint
    order = 1
  [../]
  [./TrapazoidalTimeIntegrator]
    type = VariableTimeIntegrationAux
    variable_to_integrate = u
    variable = v_trapazoid
    order = 2
  [../]
  [./SimpsonsTimeIntegrator]
    type = VariableTimeIntegrationAux
    variable_to_integrate = u
    variable = v_simpson
    order = 3
  [../]
[]

Input Parameters

variableThe name of the variable that this object applies to
C++ Type:AuxVariableName
Options:
Description:The name of the variable that this object applies to
variable_to_integrateThe variable to be integrated
C++ Type:std::vector<VariableName>
Options:
Description:The variable to be integrated

Required Parameters

blockThe list of blocks (ids or names) that this object will be applied
C++ Type:std::vector<SubdomainName>
Options:
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 boundary condition applies
C++ Type:std::vector<BoundaryName>
Options:
Description:The list of boundaries (ids or names) from the mesh where this boundary condition 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
Options:
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
coefficient1A simple coefficient multiplying the integral
Default:1
C++ Type:double
Options:
Description:A simple coefficient multiplying the integral
execute_onLINEAR TIMESTEP_ENDThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM, PRE_DISPLACE.
Default:LINEAR TIMESTEP_END
C++ Type:ExecFlagEnum
Options:NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM, PRE_DISPLACE
Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM, PRE_DISPLACE.
order2The order of global truncation error: midpoint=1, trapezoidal=2, Simpson=3
Default:2
C++ Type:unsigned int
Options:
Description:The order of global truncation error: midpoint=1, trapezoidal=2, Simpson=3
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
Options:
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.

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
Description:Set the enabled status of the MooseObject.
seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Options:
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
Options:
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/auxkernels/time_integration/time_integration.i)

# This test covers the usage of the VariableTimeIntegrationAux
# kernel. Here we test three different schemes for integrating a field
# variable in time.  Midpoint, Trapezoidal, and Simpson's rule are
# used.  For this test, we use a manufactured solution and we compare
# the Trapezoidal and Simpson's rule, which must be exact for this
# exact solution, which is a linear function of time.
#
# The set up problem is
#
#  du/dt - Laplacian(u) = Q
#
# with exact solution: u = t*(x*x+y*y).
[Mesh]
  type = GeneratedMesh
  dim = 2
  elem_type = QUAD9
  xmin = 0
  xmax = 1
  ymin = 0
  ymax = 1
  nx = 10
  ny = 10
[]

[Functions]
  [./dts]
    type = PiecewiseLinear
    x = '0.01 0.1'
    y = '0.005 0.05'
  [../]
[]

[Variables]
  [./u]
    initial_condition = 0.0
    family = LAGRANGE
    order = SECOND
  [../]
[]

[Kernels]
  active = 'diff timederivative sourceterm'
  [./diff]
     type = Diffusion
     variable = u
  [../]
  [./timederivative]
     type = TimeDerivative
     variable = u
  [../]
  [./sourceterm]
     type = BodyForce
     variable = u
     function = Source
  [../]
[]

[AuxVariables]
  active = 'v_midpoint v_trapazoid v_simpson'
  [./v_midpoint]
  [../]
  [./v_trapazoid]
  [../]
  [./v_simpson]
  [../]
[]

[AuxKernels]
  [./MidpointTimeIntegrator]
    type = VariableTimeIntegrationAux
    variable_to_integrate = u
    variable = v_midpoint
    order = 1
  [../]
  [./TrapazoidalTimeIntegrator]
    type = VariableTimeIntegrationAux
    variable_to_integrate = u
    variable = v_trapazoid
    order = 2
  [../]
  [./SimpsonsTimeIntegrator]
    type = VariableTimeIntegrationAux
    variable_to_integrate = u
    variable = v_simpson
    order = 3
  [../]
[]

[BCs]
  active = 'RightBC LeftBC TopBC BottomBC'
 [./RightBC]
    type = FunctionDirichletBC
    variable = u
    function = RightBC
    boundary = 'right'
 [../]
 [./LeftBC]
    type = FunctionDirichletBC
    variable = u
    function = LeftBC
    boundary = 'left'
 [../]
 [./TopBC]
    type = FunctionDirichletBC
    variable = u
    function = TopBC
    boundary = 'top'
 [../]
 [./BottomBC]
    type = FunctionDirichletBC
    variable = u
    function = BottomBC
    boundary = 'bottom'
 [../]
[]

[Functions]
  active = 'Soln Source TopBC BottomBC RightBC LeftBC'
 [./Soln]
    type = ParsedFunction
    value = 't*(x*x+y*y)'
 [../]
 [./Source]
    type = ParsedFunction
    value = '(x*x + y*y) - 4*t'
 [../]
 [./TopBC]
    type = ParsedFunction
    value = 't*(x*x+1)'
 [../]
 [./BottomBC]
    type = ParsedFunction
    value = 't*x*x'
 [../]
 [./RightBC]
   type = ParsedFunction
   value = 't*(y*y+1)'
 [../]
 [./LeftBC]
    type = ParsedFunction
    value = 't*y*y'
  [../]
[]
[Postprocessors]
  [./l2_error]
    type = NodalL2Error
    variable = u
    function = Soln
  [../]
[]

[Executioner]
  type = Transient

  end_time = 0.1
#  dt = 0.1
#  num_steps = 10
  [./TimeStepper]
     type = FunctionDT
     function = dts
  [../]

  nl_abs_tol = 1.e-15
[]

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

Example syntax
Input Parameters