BernoulliPressureVariable

This variable type is specific to the porous media incompressible Navier Stokes equations. When used instead of a typical finite volume variable, faces for which the neighboring elements have different porosity values will be treated as either Dirichlet or extrapolated boundary faces. When this variable is queried for a face value on the downwind side of the face, only downwind information is used to extrapolate and reconstruct the downwind side face value. The upwind side face value is computed using the reconstructed downwind face pressure value and the Bernoulli equation:

where is the pressure, is the density, and is the interstitial velocity (not the superficial velocity). Bernoulli's equation typically contains gravitational terms; however, we have omitted them under the assumption that which should be true when density does not depend on pressure (the incompressible or "weakly" compressible case).

The decision to use downstream information to compute the upstream pressure value is based on eigenvalue reasoning for the subsonic Euler equations. For the subsonic Euler equations, mesh dimension + 1 upstream explicit/physical (as opposed to implicit) boundary conditions are required while one downstream explicit/physical boundary condition is required (Novak et al., 2018). In practice this often corresponds to mesh dimension explicit inlet boundary conditions related to velocity, one explicit inlet boundary condition related to temperature, and one explicit outlet boundary condition related to pressure. Thus physics-based discretizations of Euler flows typically (at least partially) upwinds information being advected by the flow field. However, given the propagation of pressure information upstream from the explicit outlet pressure boundary condition, we believe it reasonable to do the same for computing the Bernoulli pressure jump at porosity discontinuities.

commentnote:Behavior with parallel execution

In certain cases multiple porosity jump faces may be connected by cells in a chain. For example at corners or when porous medium zones are one-cell wide. In such scenarios, the two-term expansion for the determination of the face pressure on the downstream side requires a considerably extended stencil which may not be accommodated by the number of ghosting layers set in the kernels. For this reason, the default value of "allow_two_term_expansion_on_bernoulli_faces" is false. If the user wants to enable two-term expansion for the pressure computation on the porosity jump faces, special attention should be paid to moving the porosity jump faces sufficiently far from each other (at least two layers if skewness correction is disabled and three if it is enabled) or adding additional layers of ghosted elements (which can potentially increase local computational and memory costs) using the following FVKernel parameter "ghost_layers".

Input Parameters

  • porosityThe porosity

    C++ Type:MooseFunctorName

    Controllable:No

    Description:The porosity

  • rhoThe density

    C++ Type:MooseFunctorName

    Controllable:No

    Description:The density

  • uThe x-component of velocity

    C++ Type:MooseFunctorName

    Controllable:No

    Description:The x-component of velocity

Required Parameters

  • allow_two_term_expansion_on_bernoulli_facesFalseSwitch to enable the two-term extrapolation on porosity jump faces. WARNING: This might lead to crushes in parallel runs if porosity jump faces are connected with one cell (usually corners) due to the insufficient number of ghosted layers.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Switch to enable the two-term extrapolation on porosity jump faces. WARNING: This might lead to crushes in parallel runs if porosity jump faces are connected with one cell (usually corners) due to the insufficient number of ghosted layers.

  • 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

  • v0The y-component of velocity

    Default:0

    C++ Type:MooseFunctorName

    Controllable:No

    Description:The y-component of velocity

  • w0The z-component of velocity

    Default:0

    C++ Type:MooseFunctorName

    Controllable:No

    Description:The z-component of velocity

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

References

  1. April J Novak, Ling Zou, John W Peterson, David Andrs, Joe Kelly, Rachel N Slaybaugh, Richard C Martineau, and Hands D Gougar. Pronghorn theory manual. Technical Report, Idaho National Lab.(INL), Idaho Falls, ID (United States), 2018.[BibTeX]