Coupled Pressure Action System

Set up Coupled Pressure boundary conditions

Description

The Coupled Pressure Action, given in the input file as simply CoupledPressureBC, is designed to simplify the input file when several variables have the same pressure boundary condition magnitude applied in the normal component. Transfer of pressure variable from an multi-app is a good example of a use case for the Coupled Pressure Action.

Constructed MooseObjects

The Coupled Pressure Action is used to construct only the Coupled Pressure boundary condition.

Table 1: Correspondence Among Action Functionality and MooseObjects

Functionality	Replaced Classes	Associated Parameters
A pressure traction force given by a variable	Coupled Pressure BC	`displacements` : a string of the displacement variables to which the Coupled Pressure BC should be applied
`pressure` : a variable prescribing the pressure to be applied

The Pressure Action only applies the pressure traction in the same component direction as the displacements variables are listed. That is, for the argument displacements = 'disp_x disp_y disp_z', the Pressure Action will create three separate Pressure BCs:

For the variable disp_x, the parameter setting component = 0 is used
For the variable disp_y, the parameter setting component = 1 is used
For the variable disp_z, the parameter setting component = 2 is used

note:Displacement Variable-Component Relationship is Relative

Note that the location of each of the variables in the displacements string determines the value of the corresponding component.

Example Input Syntax

[./CoupledPressure]
  [./Side1]
    boundary = '1'
    pressure = pressure_1
    displacements = 'disp_x disp_y disp_z'
  [../]
  [./Side2]
    boundary = '2'
    pressure = pressure_2
    displacements = 'disp_x disp_y disp_z'
  [../]
[../]

Input Parameters

boundaryThe list of boundary IDs from the mesh where the pressure will be applied
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundary IDs from the mesh where the pressure will be applied

Required Parameters

active__all__ If specified only the blocks named will be visited and made active
Default:__all__
C++ Type:std::vector<std::string>
Controllable:No
Description:If specified only the blocks named will be visited and made active
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.
displacementsThe displacements appropriate for the simulation geometry and coordinate system
C++ Type:std::vector<VariableName>
Controllable:No
Description:The displacements appropriate for the simulation geometry and coordinate system
inactiveIf specified blocks matching these identifiers will be skipped.
C++ Type:std::vector<std::string>
Controllable:No
Description:If specified blocks matching these identifiers will be skipped.
pressureThe variable that contains the pressure
C++ Type:VariableName
Controllable:No
Description:The variable that contains the pressure
save_in_disp_xThe save_in variables for x displacement
C++ Type:std::vector<AuxVariableName>
Controllable:No
Description:The save_in variables for x displacement
save_in_disp_yThe save_in variables for y displacement
C++ Type:std::vector<AuxVariableName>
Controllable:No
Description:The save_in variables for y displacement
save_in_disp_zThe save_in variables for z displacement
C++ Type:std::vector<AuxVariableName>
Controllable:No
Description:The save_in variables for z displacement
use_displaced_meshTrueWhether to use the displaced mesh.
Default:True
C++ Type:bool
Controllable:No
Description:Whether to use the displaced mesh.

Optional Parameters

Associated Actions

Available Actions

Tensor Mechanics App
CoupledPressureActionSet up Coupled Pressure boundary conditions

(../moose/modules/tensor_mechanics/test/tests/coupled_pressure/coupled_pressure_test.i)

#
# Pressure Test
#
# This test is designed to compute pressure loads on three faces of a unit cube.
# The pressure is computed as an auxiliary variable. It should give the same result
# as pressure_test.i
#
# The mesh is composed of one block with a single element.  Symmetry bcs are
# applied to the faces opposite the pressures.  Poisson's ratio is zero,
# which makes it trivial to check displacements.
#


[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
[]

[Mesh]
  type = FileMesh
  file = pressure_test.e
[]

[Functions]
  [./rampConstant]
    type = PiecewiseLinear
    x = '0. 1. 2.'
    y = '0. 1. 1.'
    scale_factor = 1.0
  [../]
  [./zeroRamp]
    type = PiecewiseLinear
    x = '0. 1. 2.'
    y = '0. 0. 1.'
    scale_factor = 2.0
  [../]
  [./rampUnramp]
    type = PiecewiseLinear
    x = '0. 1. 2.'
    y = '0. 1. 0.'
    scale_factor = 10.0
  [../]
[]

[AuxVariables]
  [./pressure_1]
  [../]
  [./pressure_2]
  [../]
  [./pressure_3]
  [../]
[]

[AuxKernels]
  [./side1_pressure_ak]
    type = FunctionAux
    variable = pressure_1
    boundary = 1
    function = rampConstant
  [../]
  [./side2_pressure_ak]
    type = FunctionAux
    variable = pressure_2
    boundary = 2
    function = zeroRamp
  [../]
  [./side3_pressure_ak]
    type = FunctionAux
    variable = pressure_3
    boundary = 3
    function = rampUnramp
  [../]
[]

[Modules]
  [./TensorMechanics]
    [./Master]
      [./all]
        strain = SMALL
        add_variables = true
      [../]
    [../]
  [../]
[]

[BCs]
  [./no_x]
    type = DirichletBC
    variable = disp_x
    boundary = 4
    value = 0.0
  [../]
  [./no_y]
    type = DirichletBC
    variable = disp_y
    boundary = 5
    value = 0.0
  [../]
  [./no_z]
    type = DirichletBC
    variable = disp_z
    boundary = 6
    value = 0.0
  [../]
  [./CoupledPressure]
    [./Side1]
      boundary = '1'
      pressure = pressure_1
      displacements = 'disp_x disp_y disp_z'
    [../]
    [./Side2]
      boundary = '2'
      pressure = pressure_2
      displacements = 'disp_x disp_y disp_z'
    [../]
  [../]

  [./side3_x]
    type = CoupledPressureBC
    variable = 'disp_x'
    boundary = '3'
    pressure = pressure_3
    component = 0
  [../]
  [./side3_y]
    type = CoupledPressureBC
    variable = 'disp_y'
    boundary = '3'
    pressure = pressure_3
    component = 1
  [../]
  [./side3_z]
    type = CoupledPressureBC
    variable = 'disp_z'
    boundary = '3'
    pressure = pressure_3
    component = 2
  [../]
[]

[Materials]
  [./Elasticity_tensor]
    type = ComputeElasticityTensor
    fill_method = symmetric_isotropic
    C_ijkl = '0 0.5e6'
  [../]
  [./stress]
    type = ComputeLinearElasticStress
  [../]
[]

[Executioner]
  type = Transient
  solve_type = PJFNK
  nl_abs_tol = 1e-10
  l_max_its = 20
  start_time = 0.0
  dt = 1.0
  num_steps = 2
  end_time = 2.0
[]

[Outputs]
  [./out]
    type = Exodus
    elemental_as_nodal = true
  [../]
[]