NekBinnedVolumeAverage

Compute the spatially-binned volume average of a field over the NekRS mesh

Description

This user objects performs a volume average of a specified field over bins defined on the NekRS mesh. For a bin on $var element = document.getElementById("moose-equation-dfa292e5-dfae-4880-a011-24e76b6225e9");katex.render("\\Omega_i", element, {displayMode:false,throwOnError:false});$ , the user object value in that bin is

$var element = document.getElementById("moose-equation-d945b9cc-3417-42f2-af8c-406c3075b2f2");katex.render("p_i=\\frac{\\int_{\\Omega_i}f\\ d\\Omega}{\\int_{\\Omega_i}d\\Omega}", element, {displayMode:true,throwOnError:false});$

where $var element = document.getElementById("moose-equation-05b648ce-191d-408a-a992-43a631dead8b");katex.render("p", element, {displayMode:false,throwOnError:false});$ is the value of the user object in bin $var element = document.getElementById("moose-equation-c7578059-31ef-409c-8c2d-a52983face88");katex.render("i", element, {displayMode:false,throwOnError:false});$ and $var element = document.getElementById("moose-equation-44662761-44a3-4b5e-a460-e6bccd9a0513");katex.render("f", element, {displayMode:false,throwOnError:false});$ is the specified field. To be clear, this user object is not evaluated on the NekRSMesh mesh mirror, but instead on the mesh actually used for computation in NekRS.

The field is specified with the field parameter, which may be one of:

pressure
temperature
velocity (magnitude of velocity)
velocity_x ( $var element = document.getElementById("moose-equation-fdb082d9-9774-41a9-91af-4b832bf45ed4");katex.render("x", element, {displayMode:false,throwOnError:false});$ -component of velocity)
velocity_y ( $var element = document.getElementById("moose-equation-e362e219-dfdc-4ca9-8fdc-2be2f7dd28d1");katex.render("y", element, {displayMode:false,throwOnError:false});$ -component of velocity)
velocity_z ( $var element = document.getElementById("moose-equation-01a37ff7-784d-47af-94c6-a61788616a79");katex.render("z", element, {displayMode:false,throwOnError:false});$ -component of velocity)
velocity_component (velocity vector projected onto another vector)
scalar01
scalar02
scalar03
unity

Setting field = unity is equivalent to computing 1, since the numerator will be exactly equal to the denominator (unity is of more use for other postprocessors).

When using field = velocity_component, the manner in which the velocity direction is selected is given by the velocity_component parameter, which may be one of:

normal: normal to the face bins (only valid for the side binning user objects)
user: arbitrary user-specified direction, provided with the velocity_direction parameter

When using a velocity component as the field, this user object computes the dot product of the velocity with the specified direction. To retain the components of the dot product, such as for visualizing vector glyphs of the user object result in Paraview, you can use a NekSpatialBinComponentAux.

If running NekRS in non-dimensional form (and you have indicated the appropriate nondimensional scales by setting nondimensional = true for the [Problem], then the value of this postprocessor is shown in dimensional units. On the otherhand, NekRS scalars (scalar01, scalar02 or scalar03) are never dimensionalized because their dimensions are problem-dependent.

The bins are specified by providing a list of binning user objects with the bin parameter. Available user objects for specifying spatial bins are:

If more than one bin is provided, then the bins are taken as the product of each individual bin distribution.

Example Input Syntax

As an example, the input below defines three individual bin distributions (named x_bins, y_bins, and z_bins to represent 1-D binning in each coordinate direction). These bins are then combined to average over the NekRS mesh in $var element = document.getElementById("moose-equation-31afe142-d180-4e7c-b927-5f2565d8c640");katex.render("3*3*12", element, {displayMode:false,throwOnError:false});$ equal-size spatial bins.

[UserObjects]
  [x_bins]
    type = LayeredBin
    direction = x
    num_layers = 3
  []
  [y_bins]
    type = LayeredBin
    direction = y
    num_layers = 3
  []
  [z_bins]
    type = LayeredBin
    direction = z
    num_layers = 12
  []
  [vol_integral]
    type = NekBinnedVolumeIntegral
    bins = 'x_bins y_bins z_bins'
    field = unity
  []
  [avg_p]
    type = NekBinnedVolumeAverage
    bins = 'x_bins y_bins z_bins'
    field = pressure
  []

  [one_bin]
    type = LayeredBin
    direction = z
    num_layers = 1
  []
  [reference_vol_integral]
    type = NekBinnedVolumeIntegral
    bins = 'one_bin'
    field = unity
  []
  [reference_pressure_avg]
    type = NekBinnedVolumeAverage
    bins = 'one_bin'
    field = pressure
  []
[]

The result of the user object can then be visualized with a SpatialUserObjectAux.

Input Parameters

binsUserobjects providing a spatial bin given a point
C++ Type:std::vector<UserObjectName>
Controllable:No
Description:Userobjects providing a spatial bin given a point
fieldField to postprocess
C++ Type:MooseEnum
Options:velocity_component, velocity_x, velocity_y, velocity_z, velocity, temperature, pressure, scalar01, scalar02, scalar03, unity
Controllable:No
Description:Field to postprocess

Required Parameters

check_zero_contributionsTrueWhether to throw an error if no GLL points/element centroids in the NekRS mesh map to a spatial bin; this can be used to ensure that the bins are sufficiently big to get at least one contributing point from the NekRS mesh.
Default:True
C++ Type:bool
Controllable:No
Description:Whether to throw an error if no GLL points/element centroids in the NekRS mesh map to a spatial bin; this can be used to ensure that the bins are sufficiently big to get at least one contributing point from the NekRS mesh.
execute_onTIMESTEP_ENDThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM.
Default:TIMESTEP_END
C++ Type:ExecFlagEnum
Options:NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM
Controllable:No
Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM.
interval1Frequency (in number of time steps) with which to execute this user object; because Nek uses very small time steps, you need many time steps to reach steady state, and user objects can be expensive and not necessary to evaluate on every single time step. NOTE: you probably want to match this 'interval' in the Output
Default:1
C++ Type:unsigned int
Controllable:No
Description:Frequency (in number of time steps) with which to execute this user object; because Nek uses very small time steps, you need many time steps to reach steady state, and user objects can be expensive and not necessary to evaluate on every single time step. NOTE: you probably want to match this 'interval' in the Output
map_space_by_qpFalseWhether to map the NekRS spatial domain to a bin according to the element centroids (true) or quadrature point locations (false).
Default:False
C++ Type:bool
Controllable:No
Description:Whether to map the NekRS spatial domain to a bin according to the element centroids (true) or quadrature point locations (false).
prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Controllable:No
Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
use_interpolated_stateFalseFor the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
Default:False
C++ Type:bool
Controllable:No
Description:For the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
velocity_componentDirection with which to evaluate velocity when 'field = velocity_component.' Options: user (specify a direction with 'velocity_direction'), normal (normal to side bins)
C++ Type:MooseEnum
Options:normal, user
Controllable:No
Description:Direction with which to evaluate velocity when 'field = velocity_component.' Options: user (specify a direction with 'velocity_direction'), normal (normal to side bins)
velocity_directionDirection in which to evaluate velocity, for 'field = velocity_component'. For example, velocity_direction = '1 0 0' will get the x-component of velocity.
C++ Type:libMesh::Point
Controllable:No
Description:Direction in which to evaluate velocity, for 'field = velocity_component'. For example, velocity_direction = '1 0 0' will get the x-component of velocity.

Optional Parameters

allow_duplicate_execution_on_initialFalseIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
Default:False
C++ Type:bool
Controllable:No
Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
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.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:Yes
Description:Set the enabled status of the MooseObject.
execution_order_group0Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.
Default:0
C++ Type:int
Controllable:No
Description:Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.
force_postauxFalseForces the UserObject to be executed in POSTAUX
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in POSTAUX
force_preauxFalseForces the UserObject to be executed in PREAUX
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in PREAUX
force_preicFalseForces the UserObject to be executed in PREIC during initial setup
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in PREIC during initial setup
use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
Default:False
C++ Type:bool
Controllable:No
Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Advanced Parameters

Input Files

(tutorials/subchannel/nek.i)
(tutorials/gas_compact_cht/nek.i)
(test/tests/userobjects/interval/nek.i)
(test/tests/userobjects/subchannel_layered/user_component.i)
(test/tests/userobjects/subchannel_layered/1d.i)
(tutorials/pebble_cht/nek.i)
(test/tests/nek_errors/invalid_scalar/nek_uo.i)
(test/tests/userobjects/subchannel_layered/order_error.i)
(test/tests/userobjects/gap/nondimensional/nek.i)
(tutorials/standalone/nek.i)
(test/tests/userobjects/subchannel_layered/type_error.i)
(test/tests/userobjects/layered_layered/nek.i)
(test/tests/userobjects/volume/dimensional/nek.i)
(test/tests/userobjects/subchannel_layered/nek.i)
(test/tests/userobjects/subchannel_layered/duplicate_directions.i)
(test/tests/userobjects/subchannel_layered/wrong_type.i)
(test/tests/nek_errors/invalid_settings/problem_uo.i)
(test/tests/nek_errors/invalid_field/nek_uo.i)
(test/tests/userobjects/volume/nondimensional/nek.i)
(test/tests/userobjects/gap/dimensional/nek.i)

(test/tests/userobjects/layered_layered/nek.i)

[Problem]
  type = NekRSStandaloneProblem
  casename = 'brick'
  output = 'pressure'

  nondimensional = true
  L_ref = 2.0
  U_ref = 1.0
  rho_0 = 834.5
  Cp_0 = 1228.0
  T_ref = 573.0
  dT_ref = 10.0
[]

[Mesh]
  type = NekRSMesh
  volume = true
  scaling = 2.0
[]

[AuxVariables]
  [bin_volumes]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [total_volume]
    family = MONOMIAL
    order = CONSTANT
  []
  [total_average_p]
    family = MONOMIAL
    order = CONSTANT
  []

  # just for visualization of the binning
  [x_bins]
    family = MONOMIAL
    order = CONSTANT
  []
  [y_bins]
    family = MONOMIAL
    order = CONSTANT
  []
  [z_bins]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  # just for visualization of the binning
  [x_bins]
    type = SpatialUserObjectAux
    variable = x_bins
    user_object = x_bins
    execute_on = INITIAL
  []
  [y_bins]
    type = SpatialUserObjectAux
    variable = y_bins
    user_object = y_bins
    execute_on = INITIAL
  []
  [z_bins]
    type = SpatialUserObjectAux
    variable = z_bins
    user_object = z_bins
    execute_on = INITIAL
  []

  [bin_volumes]
    type = SpatialUserObjectAux
    variable = bin_volumes
    user_object = vol_integral
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [avg_p]
    type = SpatialUserObjectAux
    variable = avg_p
    user_object = avg_p
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [total_volume]
    type = SpatialUserObjectAux
    variable = total_volume
    user_object = reference_vol_integral
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [total_average_p]
    type = SpatialUserObjectAux
    variable = total_average_p
    user_object = reference_pressure_avg
    execute_on = 'INITIAL TIMESTEP_END'
  []
[]

[UserObjects]
  [x_bins]
    type = LayeredBin
    direction = x
    num_layers = 3
  []
  [y_bins]
    type = LayeredBin
    direction = y
    num_layers = 3
  []
  [z_bins]
    type = LayeredBin
    direction = z
    num_layers = 12
  []
  [vol_integral]
    type = NekBinnedVolumeIntegral
    bins = 'x_bins y_bins z_bins'
    field = unity
  []
  [avg_p]
    type = NekBinnedVolumeAverage
    bins = 'x_bins y_bins z_bins'
    field = pressure
  []

  [one_bin]
    type = LayeredBin
    direction = z
    num_layers = 1
  []
  [reference_vol_integral]
    type = NekBinnedVolumeIntegral
    bins = 'one_bin'
    field = unity
  []
  [reference_pressure_avg]
    type = NekBinnedVolumeAverage
    bins = 'one_bin'
    field = pressure
  []
[]

[Postprocessors]
  # we compare the integral (with a single bin) with an already-verified postprocessor
  # to make sure the actual internals of the binned volume integral are done correctly
  [volume_ref] # should match the value in 'total_volume' (computed with 1 bin)
    type = NekVolumeIntegral
    field = unity
  []
  [avg_p_ref] # should match the value in 'total_average_p' (computed with 1 bin)
    type = NekVolumeAverage
    field = pressure
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

(tutorials/subchannel/nek.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature velocity'
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [subchannel_gap_binning]
    type = HexagonalSubchannelGapBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 7
  []
  [average_T]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = temperature
    map_space_by_qp = true
  []
  [average_T_gaps]
    type = NekBinnedPlaneAverage
    bins = 'subchannel_gap_binning axial_binning'
    field = temperature
    map_space_by_qp = true
    gap_thickness = ${fparse 0.05 * 7.646e-3}
  []
  [avg_gap_velocity]
    type = NekBinnedPlaneAverage
    bins = 'subchannel_gap_binning axial_binning'
    field = velocity_component
    velocity_component = normal
    map_space_by_qp = true
    gap_thickness = ${fparse 0.05 * 7.646e-3}
  []
[]

[AuxVariables]
  # These are just for visualizing the average velocity component with Glyphs in paraview;
  # the result of the 'avg_gap_velocity' user object will be represented as a vector "uo_" with 3 components
  [uo_x]
    family = MONOMIAL
    order = CONSTANT
  []
  [uo_y]
    family = MONOMIAL
    order = CONSTANT
  []
  [uo_z]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [uo_x]
    type = NekSpatialBinComponentAux
    variable = uo_x
    user_object = avg_gap_velocity
    component = 0
  []
  [uo_y]
    type = NekSpatialBinComponentAux
    variable = uo_y
    user_object = avg_gap_velocity
    component = 1
  []
  [uo_z]
    type = NekSpatialBinComponentAux
    variable = uo_z
    user_object = avg_gap_velocity
    component = 2
  []
[]

[MultiApps]
  [subchannel]
    type = TransientMultiApp
    input_files = 'subchannel.i'
    execute_on = timestep_end
    sub_cycling = true
  []
  [subchannel_gap]
    type = TransientMultiApp
    input_files = 'subchannel_gap.i'
    execute_on = timestep_end
    sub_cycling = true
  []
[]

[Transfers]
  [uo_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = average_T
    to_multi_app = subchannel
    variable = average_T
  []
  [uo_to_sub2]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = average_T_gaps
    to_multi_app = subchannel_gap
    variable = average_T
  []
  [uo1_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_gap_velocity
    to_multi_app = subchannel_gap
    variable = avg_gap_velocity
  []
  [uox_to_sub]
    type = MultiAppGeneralFieldNearestLocationTransfer
    to_multi_app = subchannel_gap
    source_variable = uo_x
    variable = uo_x
  []
  [uoy_to_sub]
    type = MultiAppGeneralFieldNearestLocationTransfer
    to_multi_app = subchannel_gap
    source_variable = uo_y
    variable = uo_y
  []
[]

[VectorPostprocessors]
  [avg_T]
    type = SpatialUserObjectVectorPostprocessor
    userobject = average_T
  []
  [avg_T_gaps]
    type = SpatialUserObjectVectorPostprocessor
    userobject = average_T_gaps
  []
  [avg_v_gaps]
    type = SpatialUserObjectVectorPostprocessor
    userobject = avg_gap_velocity
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  csv = true
[]

(tutorials/gas_compact_cht/nek.i)

# copy-pasta from common_input.i

channel_diameter = 0.016                 # diameter of the coolant channels (m)
height = 6.343                           # height of the full core (m)
inlet_T = 598.0                          # inlet fluid temperature (K)
power = 200e6                            # full core power (W)
mdot = 117.3                             # fluid mass flowrate (kg/s)
fluid_density = 5.5508                   # fluid density (kg/m3)
fluid_Cp = 5189.0                        # fluid isobaric specific heat (J/kg/K)
n_bundles = 12                           # number of bundles in the full core
n_coolant_channels_per_block = 108       # number of coolant channels per assembly
unit_cell_height = 1.6                   # unit cell height - arbitrarily selected
num_layers_for_plots = 50                # number of layers to average fields over for plotting

[Mesh]
  type = NekRSMesh
  boundary = '3'
  volume = true
  scaling = ${channel_diameter}
[]

[Problem]
  type = NekRSProblem
  casename = 'ranstube'
  has_heat_source = false

  nondimensional = true
  U_ref = ${fparse mdot / (n_bundles * n_coolant_channels_per_block) / fluid_density / (pi * channel_diameter * channel_diameter / 4.0)}
  T_ref = ${inlet_T}
  dT_ref = ${fparse power / mdot / fluid_Cp * unit_cell_height / height}
  L_ref = ${channel_diameter}
  rho_0 = ${fluid_density}
  Cp_0 = ${fluid_Cp}

  synchronization_interval = parent_app
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
    min_dt = 1e-10
  []
[]

[Outputs]
  exodus = true

  [screen]
    type = Console
    hide = 'boundary_flux inlet_T outlet_T max_T flux_integral transfer_in'
  []

  [csv]
    file_base = 'csv/nek'
    type = CSV
  []
[]

[Postprocessors]
  [boundary_flux]
    type = NekHeatFluxIntegral
    boundary = '3'
  []
  [inlet_T]
    type = NekSideAverage
    field = temperature
    boundary = '1'
  []
  [outlet_T]
    type = NekSideAverage
    field = temperature
    boundary = '2'
  []
  [max_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
[]

[UserObjects]
active = '' # simply comment out this line to evaluate these user objects
  [layered_bin]
    type = LayeredBin
    num_layers = ${num_layers_for_plots}
    direction = z
  []
  [wall_temp]
    type = NekBinnedSideAverage
    bins = 'layered_bin'
    boundary = '3'
    field = temperature
    map_space_by_qp = true
  []
  [bulk_temp]
    type = NekBinnedVolumeAverage
    bins = 'layered_bin'
    field = temperature
    map_space_by_qp = true
  []
[]

[VectorPostprocessors]
active = '' # simply comment out this line to evaluate these user objects
  [wall]
    type = SpatialUserObjectVectorPostprocessor
    userobject = wall_temp
  []
  [bulk]
    type = SpatialUserObjectVectorPostprocessor
    userobject = bulk_temp
  []
[]

(test/tests/userobjects/interval/nek.i)

[Problem]
  type = NekRSStandaloneProblem
  casename = 'brick'

  nondimensional = true
  L_ref = 2.0
  U_ref = 1.0
  rho_0 = 834.5
  Cp_0 = 1228.0
  T_ref = 573.0
  dT_ref = 10.0
[]

[Mesh]
  type = NekRSMesh
  volume = true
  scaling = 2.0
[]

[UserObjects]
  [x_bins]
    type = LayeredBin
    direction = x
    num_layers = 3
  []
  [avg_v]
    type = NekBinnedVolumeAverage
    bins = 'x_bins'
    field = velocity_z
    interval = 3
  []
[]

[VectorPostprocessors]
  [v]
    type = SpatialUserObjectVectorPostprocessor
    userobject = avg_v
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  csv = true
  interval = 3
[]

(test/tests/userobjects/subchannel_layered/user_component.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'velocity'
[]

[AuxVariables]
  [velocity_component]
  []

  # These are just for visualizing the average velocity component with Glyphs in paraview;
  # the result of the 'vol_avg' user object will be represented as a vector "uo_" with 3 components
  [uo_x]
    family = MONOMIAL
    order = CONSTANT
  []
  [uo_y]
    family = MONOMIAL
    order = CONSTANT
  []
  [uo_z]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [velocity_component] # actual velocity component computed directly from interpolated nekRS velocity fields
    type = ParsedAux
    variable = velocity_component
    expression = '(0.1*vel_x-0.2*vel_y+0.3*vel_z)/sqrt(0.1*0.1+0.2*0.2+0.3*0.3)'
    coupled_variables = 'vel_x vel_y vel_z'
    execute_on = 'timestep_end nonlinear linear'
  []
  [uo_x]
    type = NekSpatialBinComponentAux
    variable = uo_x
    user_object = vol_avg
    component = 0
  []
  [uo_y]
    type = NekSpatialBinComponentAux
    variable = uo_y
    user_object = vol_avg
    component = 1
  []
  [uo_z]
    type = NekSpatialBinComponentAux
    variable = uo_z
    user_object = vol_avg
    component = 2
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 6
  []
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = velocity_component
    velocity_component = user
    velocity_direction = '0.1 -0.2 0.3'
  []
[]

[MultiApps]
  [subchannel]
    type = TransientMultiApp
    input_files = 'subchannel_b.i'
    execute_on = timestep_end
  []
[]

[Transfers]
  [uo1_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = vol_avg
    to_multi_app = subchannel
    variable = vol_avg
  []
  [uox_to_sub]
    type = MultiAppGeneralFieldNearestLocationTransfer
    source_variable = uo_x
    to_multi_app = subchannel
    variable = uo_x
    search_value_conflicts = false
  []
  [uoy_to_sub]
    type = MultiAppGeneralFieldNearestLocationTransfer
    source_variable = uo_y
    to_multi_app = subchannel
    variable = uo_y
    search_value_conflicts = false
  []
  [uoz_to_sub]
    type = MultiAppGeneralFieldNearestLocationTransfer
    source_variable = uo_z
    to_multi_app = subchannel
    variable = uo_z
    search_value_conflicts = false
  []
  [analytic_to_sub]
    type = MultiAppGeneralFieldNearestLocationTransfer
    source_variable = velocity_component
    to_multi_app = subchannel
    variable = velocity_component
    search_value_conflicts = false
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true

  # unhide and turn the number of time steps in the .par file to greater than 1 in order to see this
  # match the user object
  hide = 'velocity_component'
[]

(test/tests/userobjects/subchannel_layered/1d.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature'
[]

[AuxVariables]
  [uo]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [uo]
    type = SpatialUserObjectAux
    variable = uo
    user_object = vol_avg
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning'
    field = temperature
  []
[]

[VectorPostprocessors]
  # from_uo gives exactly the same results as manually specifying the points in 'manually_provided',
  # but without the headache of figuring out what all the centroids of the subchannels are
  [from_uo]
    type = SpatialUserObjectVectorPostprocessor
    userobject = vol_avg
  []
  [manually_provided]
    type = SpatialUserObjectVectorPostprocessor
    userobject = vol_avg
    points = '         0  0.00517635        0
             -0.00448285  0.00258817        0
             -0.00448285 -0.00258817        0
                       0 -0.00517635        0
              0.00448285 -0.00258817        0
              0.00448285  0.00258817        0
                       0  0.010342          0
             -0.00895648  0.00517102        0
             -0.00895648 -0.00517102        0
                       0 -0.010342          0
              0.00895648 -0.00517102        0
              0.00895648  0.00517102        0
              0.00634302  0.0109864         0
             -0.00634302  0.0109864         0
             -0.01268600  0                 0
             -0.00634302 -0.0109864         0
              0.00634302 -0.0109864         0
              0.01268600  0                 0'
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
  csv = true
  execute_on = 'final'
[]

(tutorials/pebble_cht/nek.i)

[Mesh]
  type = NekRSMesh

  # This is the boundary we are coupling via conjugate heat transfer to MOOSE
  boundary = '3'
[]

[Problem]
  type = NekRSProblem
  casename = 'pebble'
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[UserObjects]
  [layered_bin]
    type = LayeredBin
    num_layers = 5
    direction = z
  []
  [wall_temp]
    type = NekBinnedSideAverage
    bins = 'layered_bin'
    boundary = '3'
    field = temperature
    map_space_by_qp = true
    interval = 10
  []
  [bulk_temp]
    type = NekBinnedVolumeAverage
    bins = 'layered_bin'
    field = temperature
    map_space_by_qp = true
    interval = 10
  []
[]

[VectorPostprocessors]
  [wall]
    type = SpatialUserObjectVectorPostprocessor
    userobject = wall_temp
  []
  [bulk]
    type = SpatialUserObjectVectorPostprocessor
    userobject = bulk_temp
  []
[]

[Outputs]
  exodus = true
  csv = true
  interval = 10
  hide = 'flux_integral'
[]

(test/tests/nek_errors/invalid_scalar/nek_uo.i)

[Problem]
  type = NekRSStandaloneProblem
  casename = 'pyramid'
[]

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 10
    pin_pitch = 1
    pin_diameter = 1
    n_rings = 1
  []
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning'
  []
[]

(test/tests/userobjects/subchannel_layered/order_error.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature'
[]

[UserObjects]
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning'
    field = temperature
  []
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/gap/nondimensional/nek.i)

[Mesh]
  type = NekRSMesh
  volume = true
  scaling = 7.646e-3
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature pressure velocity'

  nondimensional = true
  L_ref = 7.646e-3
  T_ref = 100.0
  dT_ref = 50.0
  U_ref = 2.0
  rho_0 = 834.5
  Cp_0 = 1228.0
[]

[AuxVariables]
  [avg_T]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_v]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_T]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_v]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [avg_T]
    type = SpatialUserObjectAux
    variable = avg_T
    user_object = avg_T
  []
  [avg_p]
    type = SpatialUserObjectAux
    variable = avg_p
    user_object = avg_p
  []
  [avg_v]
    type = SpatialUserObjectAux
    variable = avg_v
    user_object = avg_v
  []
  [integral_T]
    type = SpatialUserObjectAux
    variable = integral_T
    user_object = integral_T
  []
  [integral_p]
    type = SpatialUserObjectAux
    variable = integral_p
    user_object = integral_p
  []
  [integral_v]
    type = SpatialUserObjectAux
    variable = integral_v
    user_object = integral_v
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 6
  []
  [avg_T]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [avg_p]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = pressure
  []
  [avg_v]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = velocity
  []
  [integral_T]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [integral_p]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = pressure
  []
  [integral_v]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = velocity
  []
[]

[MultiApps]
  [subchannel]
    type = TransientMultiApp
    input_files = 'subchannel.i'
    execute_on = timestep_end
  []
[]

[Transfers]
  [uo1_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_T
    to_multi_app = subchannel
    variable = avg_T
  []
  [uo2_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_p
    to_multi_app = subchannel
    variable = avg_p
  []
  [uo3_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_v
    to_multi_app = subchannel
    variable = avg_v
  []
  [uo4_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_T
    to_multi_app = subchannel
    variable = integral_T
  []
  [uo5_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_p
    to_multi_app = subchannel
    variable = integral_p
  []
  [uo6_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_v
    to_multi_app = subchannel
    variable = integral_v
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

(tutorials/standalone/nek.i)

[Mesh]
  type = NekRSMesh
  volume = true
  order = SECOND
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'turbPipe'
  output = 'pressure velocity'
[]

[Postprocessors]
  [outlet_p]
    type = NekSideAverage
    boundary = '2'
    field = pressure
  []
  [inlet_p]
    type = NekSideAverage
    boundary = '1'
    field = pressure
  []
  [mdot]
    type = NekMassFluxWeightedSideIntegral
    boundary = '1'
    field = unity
  []

  # subtracts the two pressure postprocessors
  [dP]
    type = DifferencePostprocessor
    value1 = outlet_p
    value2 = inlet_p
  []
[]

[UserObjects]
  [axial_bins]
    type = LayeredBin
    direction = z
    num_layers = 20
  []
  [radial_bins]
    type = RadialBin
    vertical_axis = z
    rmax = 0.5
    nr = 12
    growth_r = 0.9
  []
  [volume_averages]
    type = NekBinnedVolumeAverage
    bins = 'radial_bins axial_bins'
    field = velocity_z
    map_space_by_qp = true
  []
[]

[AuxVariables]
  [volume_averages]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [volume_averages]
    type = SpatialUserObjectAux
    variable = volume_averages
    user_object = volume_averages
  []
[]

[MultiApps]
  [sub]
    type = TransientMultiApp
    input_files = sub.i
    execute_on = timestep_end
  []
[]

[Transfers]
  [uo_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    to_multi_app = sub
    source_user_object = volume_averages
    variable = avg_velocity
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
  csv = true

  # this hides these values from the screen for neater output
  hide = 'outlet_p inlet_p'
[]

(test/tests/userobjects/subchannel_layered/type_error.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature'
[]

[UserObjects]
  [dummy]
    type = NearestNodeNumberUO
    point = '0.0 0.0 0.1'
  []
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'dummy'
    field = temperature
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/layered_layered/nek.i)

[Problem]
  type = NekRSStandaloneProblem
  casename = 'brick'
  output = 'pressure'

  nondimensional = true
  L_ref = 2.0
  U_ref = 1.0
  rho_0 = 834.5
  Cp_0 = 1228.0
  T_ref = 573.0
  dT_ref = 10.0
[]

[Mesh]
  type = NekRSMesh
  volume = true
  scaling = 2.0
[]

[AuxVariables]
  [bin_volumes]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [total_volume]
    family = MONOMIAL
    order = CONSTANT
  []
  [total_average_p]
    family = MONOMIAL
    order = CONSTANT
  []

  # just for visualization of the binning
  [x_bins]
    family = MONOMIAL
    order = CONSTANT
  []
  [y_bins]
    family = MONOMIAL
    order = CONSTANT
  []
  [z_bins]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  # just for visualization of the binning
  [x_bins]
    type = SpatialUserObjectAux
    variable = x_bins
    user_object = x_bins
    execute_on = INITIAL
  []
  [y_bins]
    type = SpatialUserObjectAux
    variable = y_bins
    user_object = y_bins
    execute_on = INITIAL
  []
  [z_bins]
    type = SpatialUserObjectAux
    variable = z_bins
    user_object = z_bins
    execute_on = INITIAL
  []

  [bin_volumes]
    type = SpatialUserObjectAux
    variable = bin_volumes
    user_object = vol_integral
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [avg_p]
    type = SpatialUserObjectAux
    variable = avg_p
    user_object = avg_p
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [total_volume]
    type = SpatialUserObjectAux
    variable = total_volume
    user_object = reference_vol_integral
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [total_average_p]
    type = SpatialUserObjectAux
    variable = total_average_p
    user_object = reference_pressure_avg
    execute_on = 'INITIAL TIMESTEP_END'
  []
[]

[UserObjects]
  [x_bins]
    type = LayeredBin
    direction = x
    num_layers = 3
  []
  [y_bins]
    type = LayeredBin
    direction = y
    num_layers = 3
  []
  [z_bins]
    type = LayeredBin
    direction = z
    num_layers = 12
  []
  [vol_integral]
    type = NekBinnedVolumeIntegral
    bins = 'x_bins y_bins z_bins'
    field = unity
  []
  [avg_p]
    type = NekBinnedVolumeAverage
    bins = 'x_bins y_bins z_bins'
    field = pressure
  []

  [one_bin]
    type = LayeredBin
    direction = z
    num_layers = 1
  []
  [reference_vol_integral]
    type = NekBinnedVolumeIntegral
    bins = 'one_bin'
    field = unity
  []
  [reference_pressure_avg]
    type = NekBinnedVolumeAverage
    bins = 'one_bin'
    field = pressure
  []
[]

[Postprocessors]
  # we compare the integral (with a single bin) with an already-verified postprocessor
  # to make sure the actual internals of the binned volume integral are done correctly
  [volume_ref] # should match the value in 'total_volume' (computed with 1 bin)
    type = NekVolumeIntegral
    field = unity
  []
  [avg_p_ref] # should match the value in 'total_average_p' (computed with 1 bin)
    type = NekVolumeAverage
    field = pressure
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/volume/dimensional/nek.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature pressure velocity'
[]

[AuxVariables]
  [avg_T]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_v]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_T]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_v]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [avg_T]
    type = SpatialUserObjectAux
    variable = avg_T
    user_object = avg_T
  []
  [avg_p]
    type = SpatialUserObjectAux
    variable = avg_p
    user_object = avg_p
  []
  [avg_v]
    type = SpatialUserObjectAux
    variable = avg_v
    user_object = avg_v
  []
  [integral_T]
    type = SpatialUserObjectAux
    variable = integral_T
    user_object = integral_T
  []
  [integral_p]
    type = SpatialUserObjectAux
    variable = integral_p
    user_object = integral_p
  []
  [integral_v]
    type = SpatialUserObjectAux
    variable = integral_v
    user_object = integral_v
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 6
  []
  [avg_T]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [avg_p]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = pressure
  []
  [avg_v]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = velocity
  []
  [integral_T]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [integral_p]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = pressure
  []
  [integral_v]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = velocity
  []
[]

[MultiApps]
  [subchannel]
    type = TransientMultiApp
    input_files = 'subchannel.i'
    execute_on = timestep_end
  []
[]

[Transfers]
  [uo1_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_T
    to_multi_app = subchannel
    variable = avg_T
  []
  [uo2_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_p
    to_multi_app = subchannel
    variable = avg_p
  []
  [uo3_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_v
    to_multi_app = subchannel
    variable = avg_v
  []
  [uo4_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_T
    to_multi_app = subchannel
    variable = integral_T
  []
  [uo5_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_p
    to_multi_app = subchannel
    variable = integral_p
  []
  [uo6_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_v
    to_multi_app = subchannel
    variable = integral_v
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
  file_base = nek_dim
[]

(test/tests/userobjects/subchannel_layered/nek.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature'
[]

[AuxVariables]
  [subchannel_bins]
    family = MONOMIAL
    order = CONSTANT
  []
  [axial_bins]
    family = MONOMIAL
    order = CONSTANT
  []
  [total_volume]
    family = MONOMIAL
    order = CONSTANT
  []
  [total_average_T]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [bins1]
    type = SpatialUserObjectAux
    variable = subchannel_bins
    user_object = subchannel_binning
  []
  [bins2]
    type = SpatialUserObjectAux
    variable = axial_bins
    user_object = axial_binning
  []
  [total_volume]
    type = SpatialUserObjectAux
    variable = total_volume
    user_object = reference_vol_integral
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [total_average_T]
    type = SpatialUserObjectAux
    variable = total_average_T
    user_object = reference_T_avg
    execute_on = 'INITIAL TIMESTEP_END'
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 6
  []
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [vol_integral]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = unity
  []

  [one_bin]
    type = LayeredBin
    direction = z
    num_layers = 1
  []
  [reference_vol_integral]
    type = NekBinnedVolumeIntegral
    bins = 'one_bin'
    field = unity
  []
  [reference_T_avg]
    type = NekBinnedVolumeAverage
    bins = 'one_bin'
    field = temperature
  []
[]

[MultiApps]
  [subchannel]
    type = TransientMultiApp
    input_files = 'subchannel.i'
    execute_on = timestep_end
  []
[]

[Transfers]
  [uo1_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = vol_avg
    to_multi_app = subchannel
    variable = vol_avg
  []
  [uo2_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = vol_integral
    to_multi_app = subchannel
    variable = vol_integral
  []
[]

[Postprocessors]
  # we compare the integral (with a single bin) with an already-verified postprocessor
  # to make sure the actual internals of the binned volume integral are done correctly
  [volume_ref] # should match the value in 'total_volume' (computed with 1 bin)
    type = NekVolumeIntegral
    field = unity
  []
  [avg_T_ref] # should match the value in 'total_average_T' (computed with 1 bin)
    type = NekVolumeAverage
    field = temperature
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
  hide = 'temp'
[]

(test/tests/userobjects/subchannel_layered/duplicate_directions.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 6
  []
  [x_bins]
    type = LayeredBin
    direction = x
    num_layers = 3
  []

  # should error due to duplicate bins
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning x_bins'
    field = temperature
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/subchannel_layered/wrong_type.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature'
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelGapBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 6
  []
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

(test/tests/nek_errors/invalid_settings/problem_uo.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 1
  ny = 1
[]

[Variables]
  [dummy]
  []
[]

[Kernels]
  [diffusion]
    type = Diffusion
    variable = dummy
  []
[]

[Executioner]
  type = Steady
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning'
    field = temperature
  []
[]

(test/tests/nek_errors/invalid_field/nek_uo.i)

[Problem]
  type = NekRSStandaloneProblem
  casename = 'pyramid'
[]

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 10
    pin_pitch = 1
    pin_diameter = 1
    n_rings = 1
  []
  [vol_avg]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning'
    field = temperature
  []
[]

(test/tests/userobjects/volume/nondimensional/nek.i)

[Mesh]
  type = NekRSMesh
  volume = true
  scaling = 7.646e-3
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature pressure velocity'

  nondimensional = true
  L_ref = 7.646e-3
  T_ref = 100.0
  dT_ref = 50.0
  U_ref = 2.0
  rho_0 = 834.5
  Cp_0 = 1228.0
[]

[AuxVariables]
  [avg_T]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_v]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_T]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_v]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [avg_T]
    type = SpatialUserObjectAux
    variable = avg_T
    user_object = avg_T
  []
  [avg_p]
    type = SpatialUserObjectAux
    variable = avg_p
    user_object = avg_p
  []
  [avg_v]
    type = SpatialUserObjectAux
    variable = avg_v
    user_object = avg_v
  []
  [integral_T]
    type = SpatialUserObjectAux
    variable = integral_T
    user_object = integral_T
  []
  [integral_p]
    type = SpatialUserObjectAux
    variable = integral_p
    user_object = integral_p
  []
  [integral_v]
    type = SpatialUserObjectAux
    variable = integral_v
    user_object = integral_v
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 6
  []
  [avg_T]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [avg_p]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = pressure
  []
  [avg_v]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = velocity
  []
  [integral_T]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [integral_p]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = pressure
  []
  [integral_v]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = velocity
  []
[]

[MultiApps]
  [subchannel]
    type = TransientMultiApp
    input_files = 'subchannel.i'
    execute_on = timestep_end
  []
[]

[Transfers]
  [uo1_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_T
    to_multi_app = subchannel
    variable = avg_T
  []
  [uo2_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_p
    to_multi_app = subchannel
    variable = avg_p
  []
  [uo3_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_v
    to_multi_app = subchannel
    variable = avg_v
  []
  [uo4_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_T
    to_multi_app = subchannel
    variable = integral_T
  []
  [uo5_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_p
    to_multi_app = subchannel
    variable = integral_p
  []
  [uo6_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_v
    to_multi_app = subchannel
    variable = integral_v
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

(test/tests/userobjects/gap/dimensional/nek.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

[Problem]
  type = NekRSStandaloneProblem
  casename = 'sfr_7pin'
  output = 'temperature pressure velocity'
[]

[AuxVariables]
  [area]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_T]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [avg_v]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_T]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_p]
    family = MONOMIAL
    order = CONSTANT
  []
  [integral_v]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [area]
    type = SpatialUserObjectAux
    variable = area
    user_object = area
  []
  [avg_T]
    type = SpatialUserObjectAux
    variable = avg_T
    user_object = avg_T
  []
  [avg_p]
    type = SpatialUserObjectAux
    variable = avg_p
    user_object = avg_p
  []
  [avg_v]
    type = SpatialUserObjectAux
    variable = avg_v
    user_object = avg_v
  []
  [integral_T]
    type = SpatialUserObjectAux
    variable = integral_T
    user_object = integral_T
  []
  [integral_p]
    type = SpatialUserObjectAux
    variable = integral_p
    user_object = integral_p
  []
  [integral_v]
    type = SpatialUserObjectAux
    variable = integral_v
    user_object = integral_v
  []
[]

[UserObjects]
  [subchannel_binning]
    type = HexagonalSubchannelBin
    bundle_pitch = 0.02583914354890463
    pin_pitch = 0.0089656996
    pin_diameter = 7.646e-3
    n_rings = 2
  []
  [axial_binning]
    type = LayeredBin
    direction = z
    num_layers = 6
  []
  [area]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = unity
  []
  [avg_T]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [avg_p]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = pressure
  []
  [avg_v]
    type = NekBinnedVolumeAverage
    bins = 'subchannel_binning axial_binning'
    field = velocity
  []
  [integral_T]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = temperature
  []
  [integral_p]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = pressure
  []
  [integral_v]
    type = NekBinnedVolumeIntegral
    bins = 'subchannel_binning axial_binning'
    field = velocity
  []
[]

[MultiApps]
  [subchannel]
    type = TransientMultiApp
    input_files = 'subchannel.i'
    execute_on = timestep_end
  []
[]

[Transfers]
  [uo1_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_T
    to_multi_app = subchannel
    variable = avg_T
  []
  [uo2_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_p
    to_multi_app = subchannel
    variable = avg_p
  []
  [uo3_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = avg_v
    to_multi_app = subchannel
    variable = avg_v
  []
  [uo4_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_T
    to_multi_app = subchannel
    variable = integral_T
  []
  [uo5_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_p
    to_multi_app = subchannel
    variable = integral_p
  []
  [uo6_to_sub]
    type = MultiAppGeneralFieldUserObjectTransfer
    source_user_object = integral_v
    to_multi_app = subchannel
    variable = integral_v
  []
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
  file_base = nek_dim
[]

Description
Example Input Syntax
Input Parameters
Input Files