MooseVariableFVReal

Base class for Moose variables. This should never be the terminal object type

Overview

The MooseVariableFV template supports creation of finite volume variable types. At the time of writing there is only one used instantiation of the template which is MooseVariableFVReal. MOOSE uses cell-centered finite volumes which can be conveniently supported by the CONSTANT MONOMIAL finite element type in the background.

One important parameter for MooseVariableFV objects is two_term_boundary_expansion. By default this is false. When false, boundary faces which do not have associated Dirichlet boundary conditions simply use the cell centroid value as the face value. However, when two_term_boundary_expansion is set to true in the Variables sub-block of the finite volume variable, then the cell centroid value and the reconstructed cell centroid gradient (hence the two-term name) will be used to compute the extrapolated boundary face value. Note that care should be taken when setting this parameter to true. Solving for a two-term extrapolated boundary face value requires simultaneously solving for the attached cell centroid gradient. This creates a system of equations. This system has the potential to be singular if there are multiple extrapolated boundary faces per cell; see MOOSE issue. The only time it's reasonable to expect a cell with multiple extrapolated boundary faces to yield a nonsingular system is if the vectors from the cell centroid to face centroid are parallel to the surface normals and none of the surface normals are parallel to themselves (e.g. imagine an orthogonal quad with three extrapolated boundary faces).

Example Input File Syntax

To create a MooseVariableFVReal a user can do one of the following in their input file:


[Variables]
  [u]
    family = MONOMIAL
    order = CONSTANT
    fv = true
  []
  [v]
    type = MooseVariableFVReal
  []
[]

Note that a user must specify the type if they want to be able to set finite volume variable specific parameters like two_term_boundary_expansion.

Input Parameters

  • arrayFalseTrue to make this variable a array variable regardless of number of components. If 'components' > 1, this will automatically be set to true.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:True to make this variable a array variable regardless of number of components. If 'components' > 1, this will automatically be set to true.

  • blockThe list of blocks (ids or names) that this object will be applied

    C++ Type:std::vector<SubdomainName>

    Controllable:No

    Description:The list of blocks (ids or names) that this object will be applied

  • cache_cell_gradientsTrueWhether to cache cell gradients or re-compute them.

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Whether to cache cell gradients or re-compute them.

  • components1Number of components for an array variable

    Default:1

    C++ Type:unsigned int

    Controllable:No

    Description:Number of components for an array variable

  • face_interp_methodaverageSwitch that can select between face interpoaltion methods.

    Default:average

    C++ Type:MooseEnum

    Options:average, skewness-corrected

    Controllable:No

    Description:Switch that can select between face interpoaltion methods.

  • familyMONOMIALSpecifies the family of FE shape functions to use for this variable.

    Default:MONOMIAL

    C++ Type:MooseEnum

    Options:LAGRANGE, MONOMIAL, HERMITE, SCALAR, HIERARCHIC, CLOUGH, XYZ, SZABAB, BERNSTEIN, L2_LAGRANGE, L2_HIERARCHIC, NEDELEC_ONE, LAGRANGE_VEC, MONOMIAL_VEC, RATIONAL_BERNSTEIN, SIDE_HIERARCHIC

    Controllable:No

    Description:Specifies the family of FE shape functions to use for this variable.

  • fvTrueTrue to make this variable a finite volume variable

    Default:True

    C++ Type:bool

    Controllable:No

    Description:True to make this variable a finite volume variable

  • nl_sysnl0If this variable is a nonlinear variable, this is the nonlinear system to which it should be added.

    Default:nl0

    C++ Type:NonlinearSystemName

    Controllable:No

    Description:If this variable is a nonlinear variable, this is the nonlinear system to which it should be added.

  • orderCONSTANTOrder of the FE shape function to use for this variable (additional orders not listed here are allowed, depending on the family).

    Default:CONSTANT

    C++ Type:MooseEnum

    Options:CONSTANT, FIRST, SECOND, THIRD, FOURTH, FIFTH, SIXTH, SEVENTH, EIGHTH, NINTH, TENTH, ELEVENTH, TWELFTH, THIRTEENTH, FOURTEENTH, FIFTEENTH, SIXTEENTH, SEVENTEENTH, EIGHTTEENTH, NINETEENTH, TWENTIETH, TWENTYFIRST, TWENTYSECOND, TWENTYTHIRD, TWENTYFOURTH, TWENTYFIFTH, TWENTYSIXTH, TWENTYSEVENTH, TWENTYEIGHTH, TWENTYNINTH, THIRTIETH, THIRTYFIRST, THIRTYSECOND, THIRTYTHIRD, THIRTYFOURTH, THIRTYFIFTH, THIRTYSIXTH, THIRTYSEVENTH, THIRTYEIGHTH, THIRTYNINTH, FORTIETH, FORTYFIRST, FORTYSECOND, FORTYTHIRD

    Controllable:No

    Description:Order of the FE shape function to use for this variable (additional orders not listed here are allowed, depending on the family).

  • two_term_boundary_expansionTrueWhether to use a two-term Taylor expansion to calculate boundary face values. If the two-term expansion is used, then the boundary face value depends on the adjoining cell center gradient, which itself depends on the boundary face value. Consequently an implicit solve is used to simultaneously solve for the adjoining cell center gradient and boundary face value(s).

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Whether to use a two-term Taylor expansion to calculate boundary face values. If the two-term expansion is used, then the boundary face value depends on the adjoining cell center gradient, which itself depends on the boundary face value. Consequently an implicit solve is used to simultaneously solve for the adjoining cell center gradient and boundary face value(s).

  • use_dualFalseTrue to use dual basis for Lagrange multipliers

    Default:False

    C++ Type:bool

    Controllable:No

    Description:True to use dual basis for Lagrange multipliers

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.

  • eigenFalseTrue to make this variable an eigen variable

    Default:False

    C++ Type:bool

    Controllable:No

    Description:True to make this variable an eigen variable

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Set the enabled status of the MooseObject.

  • outputsVector of output names where you would like to restrict the output of variables(s) associated with this object

    C++ Type:std::vector<OutputName>

    Controllable:No

    Description:Vector of output names where you would like to restrict the output of variables(s) associated with this object

  • scalingSpecifies a scaling factor to apply to this variable

    C++ Type:std::vector<double>

    Controllable:No

    Description:Specifies a scaling factor to apply to this variable

Advanced Parameters