TimeSequenceStepper

Solves the Transient problem at a sequence of given time points.

If the solver fails to obtain a converged solution for a given step, the executioner cuts back the step size and attempts to advance the time from the previous step using a smaller time step. The time step is cut back by multiplying the time step by the cutback factor, defaulting to 0.5. If this is successful, the time stepper will then attempt to use the next time in the sequence, adjusting the time step to "get back on track".

Example input syntax

In this example, the numerical problem is solved at four specified points in time using a TimeSequenceStepper.

[Executioner]
  type = Transient
  end_time = 4.0
  [./TimeStepper]
    type = TimeSequenceStepper
    time_sequence = '0   0.85 1.3 2 4'
  [../]
[]

Input Parameters

time_sequenceThe values of t
C++ Type:std::vector<double>
Controllable:No
Description:The values of t

Required Parameters

cutback_factor_at_failure0.5Factor to apply to timestep if a time step fails to converge.
Default:0.5
C++ Type:double
Controllable:No
Description:Factor to apply to timestep if a time step fails to converge.
reset_dtFalseUse when restarting a calculation to force a change in dt.
Default:False
C++ Type:bool
Controllable:No
Description:Use when restarting a calculation to force a change in dt.

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:No
Description:Set the enabled status of the MooseObject.

Advanced Parameters

(../../../SoftwareDownloads/moose/test/tests/time_steppers/timesequence_stepper/timesequence.i)

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

[Functions]
  [./exact_fn]
    type = ParsedFunction
    value = t*t*(x*x+y*y)
  [../]

  [./forcing_fn]
    type = ParsedFunction
    value = 2*t*(x*x+y*y)-4*t*t
  [../]
[]

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

[ICs]
  [./u_var]
    type = FunctionIC
    variable = u
    function = exact_fn
  [../]
[]

[Kernels]
  [./td]
    type = TimeDerivative
    variable = u
  [../]

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

  [./ffn]
    type = BodyForce
    variable = u
    function = forcing_fn
  [../]
[]

[BCs]
  [./all]
    type = FunctionDirichletBC
    variable = u
    boundary = 'left right top bottom'
    function = exact_fn
  [../]
[]

[Executioner]
  type = Transient
  end_time = 4.0
  [./TimeStepper]
    type = TimeSequenceStepper
    time_sequence  = '0   0.85 1.3 2 4'
  [../]
[]

[Outputs]
  exodus = true
[]

Example input syntax
Input Parameters