Gravity

Apply gravity. Value is in units of acceleration.

Description

The kernel Gravity provides a body force term in the stress divergence equilibrium equation to account for gravity force due to self weight. In a continuum mechanics problem, momentum conservation is prescribed assuming static equilibrium at each time increment, (1) where is the Cauchy stress tensor and is the gravity body force per unit mass.

Example Input File Syntax


[./gravity_y]
  type = Gravity
  variable = disp_y
  value = -9.81
[../]
(modules/tensor_mechanics/test/tests/gravity/gravity_test.i)

Input Parameters

  • variableThe name of the variable that this Kernel operates on

    C++ Type:NonlinearVariableName

    Options:

    Description:The name of the variable that this Kernel operates on

Required Parameters

  • function1A function that describes the gravitational force

    Default:1

    C++ Type:FunctionName

    Options:

    Description:A function that describes the gravitational force

  • alpha0alpha parameter required for HHT time integration scheme

    Default:0

    C++ Type:double

    Options:

    Description:alpha parameter required for HHT time integration scheme

  • value0

    Default:0

    C++ Type:double

    Options:

  • blockThe list of block ids (SubdomainID) that this object will be applied

    C++ Type:std::vector

    Options:

    Description:The list of block ids (SubdomainID) that this object will be applied

Optional Parameters

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Options:

    Description:Set the enabled status of the MooseObject.

  • save_inThe name of auxiliary variables to save this Kernel's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

    C++ Type:std::vector

    Options:

    Description:The name of auxiliary variables to save this Kernel's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

  • use_displaced_meshTrueDisplaced mesh defaults to true

    Default:True

    C++ Type:bool

    Options:

    Description:Displaced mesh defaults to true

  • control_tagsAdds user-defined labels for accessing object parameters via control logic.

    C++ Type:std::vector

    Options:

    Description:Adds user-defined labels for accessing object parameters via control logic.

  • seed0The seed for the master random number generator

    Default:0

    C++ Type:unsigned int

    Options:

    Description:The seed for the master random number generator

  • diag_save_inThe name of auxiliary variables to save this Kernel's diagonal Jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

    C++ Type:std::vector

    Options:

    Description:The name of auxiliary variables to save this Kernel's diagonal Jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

  • implicitTrueDetermines whether this object is calculated using an implicit or explicit form

    Default:True

    C++ Type:bool

    Options:

    Description:Determines whether this object is calculated using an implicit or explicit form

Advanced Parameters

  • vector_tagsnontimeThe tag for the vectors this Kernel should fill

    Default:nontime

    C++ Type:MultiMooseEnum

    Options:nontime time

    Description:The tag for the vectors this Kernel should fill

  • extra_vector_tagsThe extra tags for the vectors this Kernel should fill

    C++ Type:std::vector

    Options:

    Description:The extra tags for the vectors this Kernel should fill

  • matrix_tagssystemThe tag for the matrices this Kernel should fill

    Default:system

    C++ Type:MultiMooseEnum

    Options:nontime system

    Description:The tag for the matrices this Kernel should fill

  • extra_matrix_tagsThe extra tags for the matrices this Kernel should fill

    C++ Type:std::vector

    Options:

    Description:The extra tags for the matrices this Kernel should fill

Tagging Parameters

Input Files