NavierStokesFV System

Overview

The NavierStokesFV system is dedicated to decrease the effort required by the user to prepare simulations which need to solve the Navier Stokes equations. The action is capable of setting up:

  • Incompressible and weakly-compressible simulations for

  • Clean fluids and flows in porous media

The action handles boundary conditions, necessary materials for fluid properties, variables, variable initialization and various objects for turbulence modeling.

commentnote

This action only supports Rhie-Chow interpolation for the determination of face velocities in the advection terms. The face interpolation of the advected quantities (e.g. upwind, average) can be controlled through the *_advection_interpolation action parameters.

Automatically defined variables

The NavierStokesFV action automatically sets up the variables which are necessary for the solution of a given problem. These variables can then be used to couple fluid flow simulations with other physics. The list of variable names commonly used in the action syntax is presented below:

For the default names of other variables used in this action, visit this site.

Bernoulli pressure jump treatment

Please see the Bernouilli pressure variable documentation for more information.

Examples

Incompressible fluid flow in a lid-driven cavity

In the following examples we present how the NavierStokesFV action can be utilized to simplify input files. We start with the simple lid-driven cavity problem with an Incompressible Navier Stokes formulation. The original description of the problem is available under the following link. First, we present the input file where the simulation is set up manually, by defining every kernel, boundary condition and material explicitly.

mu = 1
rho = 1
k = .01
cp = 1
velocity_interp_method = 'rc'
advected_interp_method = 'average'

[GlobalParams]
  rhie_chow_user_object = 'rc'
[]

[UserObjects]
  [rc]
    type = INSFVRhieChowInterpolator
    u = vel_x
    v = vel_y
    pressure = pressure
  []
[]

[Mesh]
  [gen]
    type = GeneratedMeshGenerator
    dim = 2
    xmin = 0
    xmax = 1
    ymin = 0
    ymax = 1
    nx = 32
    ny = 32
  []
[]

[Variables]
  [vel_x]
    type = INSFVVelocityVariable
  []
  [vel_y]
    type = INSFVVelocityVariable
  []
  [pressure]
    type = INSFVPressureVariable
  []
  [T_fluid]
    type = INSFVEnergyVariable
  []
  [lambda]
    family = SCALAR
    order = FIRST
  []
[]

[AuxVariables]
  [U]
    order = CONSTANT
    family = MONOMIAL
    fv = true
  []
[]

[AuxKernels]
  [mag]
    type = VectorMagnitudeAux
    variable = U
    x = vel_x
    y = vel_y
  []
[]

[FVKernels]
  [mass]
    type = INSFVMassAdvection
    variable = pressure
    advected_interp_method = ${advected_interp_method}
    velocity_interp_method = ${velocity_interp_method}
    rho = ${rho}
  []
  [mean_zero_pressure]
    type = FVIntegralValueConstraint
    variable = pressure
    lambda = lambda
  []

  [u_advection]
    type = INSFVMomentumAdvection
    variable = vel_x
    velocity_interp_method = ${velocity_interp_method}
    advected_interp_method = ${advected_interp_method}
    rho = ${rho}
    momentum_component = 'x'
  []

  [u_viscosity]
    type = INSFVMomentumDiffusion
    variable = vel_x
    mu = ${mu}
    momentum_component = 'x'
  []

  [u_pressure]
    type = INSFVMomentumPressure
    variable = vel_x
    momentum_component = 'x'
    pressure = pressure
  []

  [v_advection]
    type = INSFVMomentumAdvection
    variable = vel_y
    velocity_interp_method = ${velocity_interp_method}
    advected_interp_method = ${advected_interp_method}
    rho = ${rho}
    momentum_component = 'y'
  []

  [v_viscosity]
    type = INSFVMomentumDiffusion
    variable = vel_y
    mu = ${mu}
    momentum_component = 'y'
  []

  [v_pressure]
    type = INSFVMomentumPressure
    variable = vel_y
    momentum_component = 'y'
    pressure = pressure
  []

  [temp_conduction]
    type = FVDiffusion
    coeff = 'k'
    variable = T_fluid
  []

  [temp_advection]
    type = INSFVEnergyAdvection
    variable = T_fluid
    velocity_interp_method = ${velocity_interp_method}
    advected_interp_method = ${advected_interp_method}
  []
[]

[FVBCs]
  [top_x]
    type = INSFVNoSlipWallBC
    variable = vel_x
    boundary = 'top'
    function = 'lid_function'
  []

  [no_slip_x]
    type = INSFVNoSlipWallBC
    variable = vel_x
    boundary = 'left right bottom'
    function = 0
  []

  [no_slip_y]
    type = INSFVNoSlipWallBC
    variable = vel_y
    boundary = 'left right top bottom'
    function = 0
  []

  [T_hot]
    type = FVDirichletBC
    variable = T_fluid
    boundary = 'bottom'
    value = 1
  []

  [T_cold]
    type = FVDirichletBC
    variable = T_fluid
    boundary = 'top'
    value = 0
  []
[]

[Materials]
  [functor_constants]
    type = ADGenericFunctorMaterial
    prop_names = 'cp k'
    prop_values = '${cp} ${k}'
  []
  [ins_fv]
    type = INSFVEnthalpyMaterial
    temperature = 'T_fluid'
    rho = ${rho}
  []
[]

[Functions]
  [lid_function]
    type = ParsedFunction
    expression = '4*x*(1-x)'
  []
[]

[Executioner]
  type = Steady
  solve_type = 'NEWTON'
  petsc_options_iname = '-pc_type -pc_factor_shift_type'
  petsc_options_value = 'lu NONZERO'
  nl_rel_tol = 1e-12
[]

[Outputs]
  exodus = true
[]
Copy
(moose/modules/navier_stokes/test/tests/finite_volume/ins/lid-driven/lid-driven-with-energy.i)
commentnote

Careful! The utilization of central difference (average) advected interpolation may lead to oscillatory behavior in certain scenarios. Even though it is not the case for this example, if this phenomenon arises, we recommend using first order upwind or second order TVD chemes.

The same simulation can be set up using the action syntax which improves input file readability:

mu = 1
rho = 1
k = .01
cp = 1

[Mesh]
  [gen]
    type = GeneratedMeshGenerator
    dim = 2
    xmin = 0
    xmax = 1
    ymin = 0
    ymax = 1
    nx = 32
    ny = 32
  []
[]

[Modules]
  [NavierStokesFV]
    compressibility = 'incompressible'
    add_energy_equation = true

    density = 'rho'
    dynamic_viscosity = 'mu'
    thermal_conductivity = 'k'
    specific_heat = 'cp'

    initial_pressure = 0.0
    initial_temperature = 0.0

    inlet_boundaries = 'top'
    momentum_inlet_types = 'fixed-velocity'
    momentum_inlet_function = 'lid_function 0'
    energy_inlet_types = 'fixed-temperature'
    energy_inlet_function = '0'

    wall_boundaries = 'left right bottom'
    momentum_wall_types = 'noslip noslip noslip'
    energy_wall_types = 'heatflux heatflux fixed-temperature'
    energy_wall_function = '0 0 1'

    pin_pressure = true
    pinned_pressure_type = average
    pinned_pressure_value = 0

    mass_advection_interpolation = 'average'
    momentum_advection_interpolation = 'average'
    energy_advection_interpolation = 'average'
  []
[]

[AuxVariables]
  [U]
    order = CONSTANT
    family = MONOMIAL
    fv = true
  []
[]

[AuxKernels]
  [mag]
    type = VectorMagnitudeAux
    variable = U
    x = vel_x
    y = vel_y
  []
[]

[Materials]
  [functor_constants]
    type = ADGenericFunctorMaterial
    prop_names = 'cp k rho mu'
    prop_values = '${cp} ${k} ${rho} ${mu}'
  []
[]

[Functions]
  [lid_function]
    type = ParsedFunction
    expression = '4*x*(1-x)'
  []
[]

[Executioner]
  type = Steady
  solve_type = 'NEWTON'
  petsc_options_iname = '-pc_type -pc_factor_shift_type'
  petsc_options_value = 'lu NONZERO'
  nl_rel_tol = 1e-12
[]

[Outputs]
  exodus = true
[]
Copy
(moose/modules/navier_stokes/test/tests/finite_volume/ins/lid-driven/lid-driven-with-energy-action.i)

It is visible that in this case we defined the "compressibility" parameter to be incompressible. Furthermore, the energy (enthalpy) equation is solved as well. The user can request this by setting "add_energy_equation" to true. The boundary types are grouped into wall, inlet and outlet types. For more information on the available boundary types, see the list of parameters at the bottom of the page.

Incompressible fluid flow in porous medium

The following input file sets up a simulation of an incompressible fluid flow within a channel which contains a homogenized structure that is treated as a porous medium. The model accounts for the heat exchange between the fluid and the homogenized structure as well. For more description on the used model, visit the Porous medium Incompressible Navier Stokes page. First, the input file with the manually defined kernels and boundary conditions is presented:

mu = 1
rho = 1
k = 1e-3
cp = 1
u_inlet = 1
T_inlet = 200
advected_interp_method = 'average'
velocity_interp_method = 'rc'

[Mesh]
  [mesh]
    type = CartesianMeshGenerator
    dim = 2
    dx = '5 5'
    dy = '1.0'
    ix = '50 50'
    iy = '20'
    subdomain_id = '1 2'
  []
[]

[GlobalParams]
  rhie_chow_user_object = 'rc'
[]

[UserObjects]
  [rc]
    type = PINSFVRhieChowInterpolator
    u = superficial_vel_x
    v = superficial_vel_y
    pressure = pressure
    porosity = porosity
  []
[]

[Variables]
  inactive = 'T_solid'
  [superficial_vel_x]
    type = PINSFVSuperficialVelocityVariable
    initial_condition = ${u_inlet}
  []
  [superficial_vel_y]
    type = PINSFVSuperficialVelocityVariable
    initial_condition = 1e-6
  []
  [pressure]
    type = INSFVPressureVariable
  []
  [T_fluid]
    type = INSFVEnergyVariable
  []
  [T_solid]
    family = 'MONOMIAL'
    order = 'CONSTANT'
    fv = true
  []
[]

[AuxVariables]
  [T_solid]
    family = 'MONOMIAL'
    order = 'CONSTANT'
    fv = true
    initial_condition = 100
  []
  [porosity]
    family = MONOMIAL
    order = CONSTANT
    fv = true
    initial_condition = 0.5
  []
[]

[FVKernels]
  inactive = 'solid_energy_diffusion solid_energy_convection'
  [mass]
    type = PINSFVMassAdvection
    variable = pressure
    advected_interp_method = ${advected_interp_method}
    velocity_interp_method = ${velocity_interp_method}
    rho = ${rho}
  []

  [u_advection]
    type = PINSFVMomentumAdvection
    variable = superficial_vel_x
    advected_interp_method = ${advected_interp_method}
    velocity_interp_method = ${velocity_interp_method}
    rho = ${rho}
    porosity = porosity
    momentum_component = 'x'
  []
  [u_viscosity]
    type = PINSFVMomentumDiffusion
    variable = superficial_vel_x
    mu = ${mu}
    porosity = porosity
    momentum_component = 'x'
  []
  [u_pressure]
    type = PINSFVMomentumPressure
    variable = superficial_vel_x
    momentum_component = 'x'
    pressure = pressure
    porosity = porosity
  []

  [v_advection]
    type = PINSFVMomentumAdvection
    variable = superficial_vel_y
    advected_interp_method = ${advected_interp_method}
    velocity_interp_method = ${velocity_interp_method}
    rho = ${rho}
    porosity = porosity
    momentum_component = 'y'
  []
  [v_viscosity]
    type = PINSFVMomentumDiffusion
    variable = superficial_vel_y
    mu = ${mu}
    porosity = porosity
    momentum_component = 'y'
  []
  [v_pressure]
    type = PINSFVMomentumPressure
    variable = superficial_vel_y
    momentum_component = 'y'
    pressure = pressure
    porosity = porosity
  []

  [energy_advection]
    type = PINSFVEnergyAdvection
    variable = T_fluid
    velocity_interp_method = ${velocity_interp_method}
    advected_interp_method = ${advected_interp_method}
  []
  [energy_diffusion]
    type = PINSFVEnergyDiffusion
    k = ${k}
    variable = T_fluid
    porosity = porosity
  []
  [energy_convection]
    type = PINSFVEnergyAmbientConvection
    variable = T_fluid
    is_solid = false
    T_fluid = 'T_fluid'
    T_solid = 'T_solid'
    h_solid_fluid = 'h_cv'
  []

  [solid_energy_diffusion]
    type = FVDiffusion
    coeff = ${k}
    variable = T_solid
  []
  [solid_energy_convection]
    type = PINSFVEnergyAmbientConvection
    variable = T_solid
    is_solid = true
    T_fluid = 'T_fluid'
    T_solid = 'T_solid'
    h_solid_fluid = 'h_cv'
  []
[]

[FVBCs]
  inactive = 'heated-side'
  [inlet-u]
    type = INSFVInletVelocityBC
    boundary = 'left'
    variable = superficial_vel_x
    function = ${u_inlet}
  []
  [inlet-v]
    type = INSFVInletVelocityBC
    boundary = 'left'
    variable = superficial_vel_y
    function = 0
  []
  [inlet-T]
    type = FVNeumannBC
    variable = T_fluid
    value = '${fparse u_inlet * rho * cp * T_inlet}'
    boundary = 'left'
  []

  [no-slip-u]
    type = INSFVNoSlipWallBC
    boundary = 'top'
    variable = superficial_vel_x
    function = 0
  []
  [no-slip-v]
    type = INSFVNoSlipWallBC
    boundary = 'top'
    variable = superficial_vel_y
    function = 0
  []
  [heated-side]
    type = FVDirichletBC
    boundary = 'top'
    variable = 'T_solid'
    value = 150
  []

  [symmetry-u]
    type = PINSFVSymmetryVelocityBC
    boundary = 'bottom'
    variable = superficial_vel_x
    u = superficial_vel_x
    v = superficial_vel_y
    mu = ${mu}
    momentum_component = 'x'
  []
  [symmetry-v]
    type = PINSFVSymmetryVelocityBC
    boundary = 'bottom'
    variable = superficial_vel_y
    u = superficial_vel_x
    v = superficial_vel_y
    mu = ${mu}
    momentum_component = 'y'
  []
  [symmetry-p]
    type = INSFVSymmetryPressureBC
    boundary = 'bottom'
    variable = pressure
  []

  [outlet-p]
    type = INSFVOutletPressureBC
    boundary = 'right'
    variable = pressure
    function = 0.1
  []
[]

[Materials]
  [constants]
    type = ADGenericFunctorMaterial
    prop_names = 'h_cv'
    prop_values = '1'
  []
  [functor_constants]
    type = ADGenericFunctorMaterial
    prop_names = 'cp'
    prop_values = '${cp}'
  []
  [ins_fv]
    type = INSFVEnthalpyMaterial
    rho = ${rho}
    temperature = 'T_fluid'
  []
[]

[Executioner]
  type = Steady
  solve_type = 'NEWTON'
  petsc_options_iname = '-pc_type -pc_factor_shift_type'
  petsc_options_value = 'lu NONZERO'
  nl_rel_tol = 1e-14
[]

# Some basic Postprocessors to examine the solution
[Postprocessors]
  [inlet-p]
    type = SideAverageValue
    variable = pressure
    boundary = 'left'
  []
  [outlet-u]
    type = SideAverageValue
    variable = superficial_vel_x
    boundary = 'right'
  []
  [outlet-temp]
    type = SideAverageValue
    variable = T_fluid
    boundary = 'right'
  []
  [solid-temp]
    type = ElementAverageValue
    variable = T_solid
  []
[]

[Outputs]
  exodus = true
  csv = false
[]
Copy
(moose/modules/navier_stokes/test/tests/finite_volume/pins/channel-flow/heated/2d-rc-heated.i)
commentnote

Careful! The utilization of central difference (average) advected interpolation may lead to oscillatory behavior in certain scenarios. Even though it is not the case for this example, if this phenomenon arises, we recommend using first order upwind or second order TVD chemes.

The same simulation can also be set up using the NavierStokesFV action syntax:

mu = 1
rho = 1
k = 1e-3
cp = 1
u_inlet = 1
T_inlet = 200
h_cv = 1.0

[Mesh]
  [mesh]
    type = CartesianMeshGenerator
    dim = 2
    dx = '5 5'
    dy = '1.0'
    ix = '50 50'
    iy = '20'
    subdomain_id = '1 2'
  []
[]

[Variables]
  [T_solid]
    type = MooseVariableFVReal
  []
[]

[AuxVariables]
  [porosity]
    type = MooseVariableFVReal
    initial_condition = 0.5
  []
[]

[Modules]
  [NavierStokesFV]
    compressibility = 'incompressible'
    porous_medium_treatment = true
    add_energy_equation = true

    density = ${rho}
    dynamic_viscosity = ${mu}
    thermal_conductivity = ${k}
    specific_heat = ${cp}
    porosity = 'porosity'

    initial_velocity = '${u_inlet} 1e-6 0'
    initial_pressure = 0.0
    initial_temperature = 0.0

    inlet_boundaries = 'left'
    momentum_inlet_types = 'fixed-velocity'
    momentum_inlet_function = '${u_inlet} 0'
    energy_inlet_types = 'heatflux'
    energy_inlet_function = '${fparse u_inlet * rho * cp * T_inlet}'

    wall_boundaries = 'top bottom'
    momentum_wall_types = 'noslip symmetry'
    energy_wall_types = 'heatflux heatflux'
    energy_wall_function = '0 0'

    outlet_boundaries = 'right'
    momentum_outlet_types = 'fixed-pressure'
    pressure_function = '0.1'

    ambient_convection_alpha = ${h_cv}
    ambient_temperature = 'T_solid'

    mass_advection_interpolation = 'average'
    momentum_advection_interpolation = 'average'
    energy_advection_interpolation = 'average'
  []
[]

[FVKernels]
  [solid_energy_diffusion]
    type = FVDiffusion
    coeff = ${k}
    variable = T_solid
  []
  [solid_energy_convection]
    type = PINSFVEnergyAmbientConvection
    variable = 'T_solid'
    is_solid = true
    T_fluid = 'T_fluid'
    T_solid = 'T_solid'
    h_solid_fluid = ${h_cv}
  []
[]

[FVBCs]
  [heated-side]
    type = FVDirichletBC
    boundary = 'top'
    variable = 'T_solid'
    value = 150
  []
[]

[Executioner]
  type = Steady
  solve_type = 'NEWTON'
  petsc_options_iname = '-pc_type -pc_factor_shift_type'
  petsc_options_value = 'lu NONZERO'
  nl_rel_tol = 1e-14
[]

# Some basic Postprocessors to examine the solution
[Postprocessors]
  [inlet-p]
    type = SideAverageValue
    variable = pressure
    boundary = 'left'
  []
  [outlet-u]
    type = SideAverageValue
    variable = superficial_vel_x
    boundary = 'right'
  []
  [outlet-temp]
    type = SideAverageValue
    variable = T_fluid
    boundary = 'right'
  []
  [solid-temp]
    type = ElementAverageValue
    variable = T_solid
  []
[]

[Outputs]
  exodus = true
  csv = false
[]
Copy
(moose/modules/navier_stokes/test/tests/finite_volume/pins/channel-flow/heated/2d-rc-heated-action.i)

Compared to the previous example, we see that in this case the porous medium treatment is enabled by setting "porous_medium_treatment" to true. The corresponding porosity can be supplied through the "porosity" parameter. Furthermore, the heat exchange between the fluid and the homogenized structure is enabled using the "ambient_temperature" and "ambient_convection_alpha" parameters.

Weakly-compressible fluid flow

The last example is dedicated to demonstrating a transient flow in a channel using a weakly-compressible approximation. The following examples shows how this simulation is set up by manually defining the kernels and boundary conditions. For more information on the weakly-compressible treatment, visit the Weakly-compressible Navier Stokes page.

rho = 'rho'
l = 10
velocity_interp_method = 'rc'
advected_interp_method = 'average'

# Artificial fluid properties
# For a real case, use a GeneralFluidFunctorProperties and a viscosity rampdown
# or initialize very well!
k = 1
cp = 1000
mu = 1e2

# Operating conditions
inlet_temp = 300
outlet_pressure = 1e5
inlet_v = 0.001

[Mesh]
  [gen]
    type = GeneratedMeshGenerator
    dim = 2
    xmin = 0
    xmax = ${l}
    ymin = 0
    ymax = 1
    nx = 20
    ny = 10
  []
[]

[GlobalParams]
  rhie_chow_user_object = 'rc'
[]

[UserObjects]
  [rc]
    type = INSFVRhieChowInterpolator
    u = vel_x
    v = vel_y
    pressure = pressure
  []
[]

[Variables]
  [vel_x]
    type = INSFVVelocityVariable
    initial_condition = ${inlet_v}
  []
  [vel_y]
    type = INSFVVelocityVariable
    initial_condition = 1e-15
  []
  [pressure]
    type = INSFVPressureVariable
    initial_condition = ${outlet_pressure}
  []
  [T_fluid]
    type = INSFVEnergyVariable
    initial_condition = ${inlet_temp}
  []
[]

[AuxVariables]
  [mixing_length]
    type = MooseVariableFVReal
  []
  [power_density]
    type = MooseVariableFVReal
    initial_condition = 1e4
  []
[]

[FVKernels]
  inactive = 'u_turb v_turb temp_turb'
  [mass_time]
    type = WCNSFVMassTimeDerivative
    variable = pressure
    drho_dt = drho_dt
  []
  [mass]
    type = INSFVMassAdvection
    variable = pressure
    advected_interp_method = ${advected_interp_method}
    velocity_interp_method = ${velocity_interp_method}
    rho = ${rho}
  []

  [u_time]
    type = WCNSFVMomentumTimeDerivative
    variable = vel_x
    drho_dt = drho_dt
    rho = rho
    momentum_component = 'x'
  []
  [u_advection]
    type = INSFVMomentumAdvection
    variable = vel_x
    velocity_interp_method = ${velocity_interp_method}
    advected_interp_method = ${advected_interp_method}
    rho = ${rho}
    momentum_component = 'x'
  []
  [u_viscosity]
    type = INSFVMomentumDiffusion
    variable = vel_x
    mu = ${mu}
    momentum_component = 'x'
  []
  [u_pressure]
    type = INSFVMomentumPressure
    variable = vel_x
    momentum_component = 'x'
    pressure = pressure
  []
  [u_turb]
    type = INSFVMixingLengthReynoldsStress
    variable = vel_x
    rho = ${rho}
    mixing_length = 'mixing_length'
    momentum_component = 'x'
    u = vel_x
    v = vel_y
  []

  [v_time]
    type = WCNSFVMomentumTimeDerivative
    variable = vel_y
    drho_dt = drho_dt
    rho = rho
    momentum_component = 'y'
  []
  [v_advection]
    type = INSFVMomentumAdvection
    variable = vel_y
    velocity_interp_method = ${velocity_interp_method}
    advected_interp_method = ${advected_interp_method}
    rho = ${rho}
    momentum_component = 'y'
  []
  [v_viscosity]
    type = INSFVMomentumDiffusion
    variable = vel_y
    momentum_component = 'y'
    mu = ${mu}
  []
  [v_pressure]
    type = INSFVMomentumPressure
    variable = vel_y
    momentum_component = 'y'
    pressure = pressure
  []
  [v_turb]
    type = INSFVMixingLengthReynoldsStress
    variable = vel_y
    rho = ${rho}
    mixing_length = 'mixing_length'
    momentum_component = 'y'
    u = vel_x
    v = vel_y
  []

  [temp_time]
    type = WCNSFVEnergyTimeDerivative
    variable = T_fluid
    cp = cp
    rho = rho
    drho_dt = drho_dt
  []
  [temp_conduction]
    type = FVDiffusion
    coeff = 'k'
    variable = T_fluid
  []
  [temp_advection]
    type = INSFVEnergyAdvection
    variable = T_fluid
    velocity_interp_method = ${velocity_interp_method}
    advected_interp_method = ${advected_interp_method}
  []
  [heat_source]
    type = FVCoupledForce
    variable = T_fluid
    v = power_density
  []
  [temp_turb]
    type = WCNSFVMixingLengthEnergyDiffusion
    variable = T_fluid
    rho = rho
    cp = cp
    mixing_length = 'mixing_length'
    schmidt_number = 1
    u = vel_x
    v = vel_y
  []
[]

[FVBCs]
  [no_slip_x]
    type = INSFVNoSlipWallBC
    variable = vel_x
    boundary = 'top bottom'
    function = 0
  []

  [no_slip_y]
    type = INSFVNoSlipWallBC
    variable = vel_y
    boundary = 'top bottom'
    function = 0
  []

  # Inlet
  [inlet_u]
    type = INSFVInletVelocityBC
    variable = vel_x
    boundary = 'left'
    function = ${inlet_v}
  []
  [inlet_v]
    type = INSFVInletVelocityBC
    variable = vel_y
    boundary = 'left'
    function = 0
  []
  [inlet_T]
    type = FVDirichletBC
    variable = T_fluid
    boundary = 'left'
    value = ${inlet_temp}
  []

  [outlet_p]
    type = INSFVOutletPressureBC
    variable = pressure
    boundary = 'right'
    function = ${outlet_pressure}
  []
[]

[FluidProperties]
  [fp]
    type = FlibeFluidProperties
  []
[]

[Materials]
  [const_functor]
    type = ADGenericFunctorMaterial
    prop_names = 'cp k'
    prop_values = '${cp} ${k}'
  []
  [rho]
    type = RhoFromPTFunctorMaterial
    fp = fp
    temperature = T_fluid
    pressure = pressure
  []
  [ins_fv]
    type = INSFVEnthalpyMaterial
    temperature = 'T_fluid'
    rho = ${rho}
  []
[]

[AuxKernels]
  inactive = 'mixing_len'
  [mixing_len]
    type = WallDistanceMixingLengthAux
    walls = 'top'
    variable = mixing_length
    execute_on = 'initial'
    delta = 0.5
  []
[]

[Executioner]
  type = Transient
  solve_type = 'NEWTON'
  petsc_options_iname = '-pc_type -pc_factor_shift_type'
  petsc_options_value = 'lu       NONZERO'

  [TimeStepper]
    type = IterationAdaptiveDT
    dt = 1e-3
    optimal_iterations = 6
  []
  end_time = 15

  nl_abs_tol = 1e-9
  nl_max_its = 50
  line_search = 'none'

  automatic_scaling = true
  off_diagonals_in_auto_scaling = true
  compute_scaling_once = false
[]

[Outputs]
  exodus = true
[]
Copy
(moose/modules/navier_stokes/test/tests/finite_volume/wcns/channel-flow/2d-transient.i)
commentnote

Careful! The utilization of central difference (average) advected interpolation may lead to oscillatory behavior in certain scenarios. Even though it is not the case for this example, if this phenomenon arises, we recommend using first order upwind or second order TVD chemes.

The same simulation can be set up using the action syntax as folows:

l = 10

# Artificial fluid properties
# For a real case, use a GeneralFluidFunctorProperties and a viscosity rampdown
# or initialize very well!
k = 1
cp = 1000
mu = 1e2

# Operating conditions
inlet_temp = 300
outlet_pressure = 1e5
inlet_v = 0.001

[Mesh]
  [gen]
    type = GeneratedMeshGenerator
    dim = 2
    xmin = 0
    xmax = ${l}
    ymin = 0
    ymax = 1
    nx = 20
    ny = 10
  []
[]

[Modules]
  [NavierStokesFV]
    compressibility = 'weakly-compressible'
    add_energy_equation = true

    density = 'rho'
    dynamic_viscosity = 'mu'
    thermal_conductivity = 'k'
    specific_heat = 'cp'

    initial_velocity = '${inlet_v} 1e-15 0'
    initial_temperature = '${inlet_temp}'
    initial_pressure = '${outlet_pressure}'

    inlet_boundaries = 'left'
    momentum_inlet_types = 'fixed-velocity'
    momentum_inlet_function = '${inlet_v} 0'
    energy_inlet_types = 'fixed-temperature'
    energy_inlet_function = '${inlet_temp}'

    wall_boundaries = 'top bottom'
    momentum_wall_types = 'noslip noslip'
    energy_wall_types = 'heatflux heatflux'
    energy_wall_function = '0 0'

    outlet_boundaries = 'right'
    momentum_outlet_types = 'fixed-pressure'
    pressure_function = '${outlet_pressure}'

    external_heat_source = 'power_density'

    mass_advection_interpolation = 'average'
    momentum_advection_interpolation = 'average'
    energy_advection_interpolation = 'average'
  []
[]

[AuxVariables]
  [power_density]
    type = MooseVariableFVReal
    initial_condition = 1e4
  []
[]

[FluidProperties]
  [fp]
    type = FlibeFluidProperties
  []
[]

[Materials]
  [const_functor]
    type = ADGenericFunctorMaterial
    prop_names = 'cp k mu'
    prop_values = '${cp} ${k} ${mu}'
  []
  [rho]
    type = RhoFromPTFunctorMaterial
    fp = fp
    temperature = T_fluid
    pressure = pressure
  []
[]

[Executioner]
  type = Transient
  solve_type = 'NEWTON'
  petsc_options_iname = '-pc_type -pc_factor_shift_type'
  petsc_options_value = 'lu       NONZERO'

  [TimeStepper]
    type = IterationAdaptiveDT
    dt = 1e-3
    optimal_iterations = 6
  []
  end_time = 15

  nl_abs_tol = 1e-9
  nl_max_its = 50
  line_search = 'none'

  automatic_scaling = true
  off_diagonals_in_auto_scaling = true
  compute_scaling_once = false
[]

[Outputs]
  exodus = true
[]
Copy
(moose/modules/navier_stokes/test/tests/finite_volume/wcns/channel-flow/2d-transient-action.i)

We note that the weakly-compressible handling can be enabled by setting "compressibility" to weakly-compressible. As shown in the example, an arbitrary energy source function can also be supplied to the incorporated energy equation using the "external_heat_source" parameter.

Available Actions

  • Navier Stokes App
  • NSFVActionThis class allows us to set up Navier-Stokes equations for porous medium or clean fluid flows using incompressible or weakly compressible approximations with a finite volume discretization.