MaxIncrement

Limits a variable's update by some max fraction

The MaxIncrement damper limits the change of a variable from one nonlinear iteration to the following iteration. A smaller value set as the max_increment will results in more nonlinear steps.

Example Input Syntax

[Dampers]
  [./max_inc_damp]
    type = MaxIncrement
    max_increment = 0.1
    variable = u
  [../]
[]

Input Parameters

max_incrementThe maximum newton increment for the variable.
C++ Type:double
Controllable:No
Description:The maximum newton increment for the variable.
variableThe name of the variable that this damper operates on
C++ Type:NonlinearVariableName
Controllable:No
Description:The name of the variable that this damper operates on

Required Parameters

increment_typeabsoluteType of increment to compare against max_increment. 'absolute': use variable increment. 'fractional': use variable increment divided by the variable value.
Default:absolute
C++ Type:MooseEnum
Options:absolute, fractional
Controllable:No
Description:Type of increment to compare against max_increment. 'absolute': use variable increment. 'fractional': use variable increment divided by the variable value.
min_damping0Minimum value of computed damping. Damping lower than this will result in an exception being thrown and cutting the time step
Default:0
C++ Type:double
Controllable:No
Description:Minimum value of computed damping. Damping lower than this will result in an exception being thrown and cutting the time step
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
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.

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.

Advanced Parameters

(../moose/test/tests/dampers/max_increment/max_increment_damper_test.i)

# This model tests the MaxIncrement damper. The converged solution field
# u varies from 0 to 1 across the domain due to the BCs applied. A value
# for the maximum allowed increment to the solution vector for each
# NL iteration is specified. The more restrictive this value is, the
# larger the number of NL iterations will be. This test ensures that a
# minimum number of NL iterations are taken under those conditions.

[Mesh]
  type = GeneratedMesh
  dim = 2
  xmin = 0
  xmax = 1
  ymin = 0
  ymax = 1
  nx = 2
  ny = 2
  elem_type = QUAD9
[]

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

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

[BCs]
  [./left]
    type = DirichletBC
    variable = u
    preset = false
    boundary = left
    value = 0
  [../]

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

[Dampers]
  [./max_inc_damp]
    type = MaxIncrement
    max_increment = 0.1
    variable = u
  [../]
[]

[Executioner]
  type = Steady
  solve_type = 'PJFNK'
[]