NekHeatFluxIntegral

Compute heat flux over a boundary in the NekRS mesh

Description

This postprocessor computes the heat flux over a boundary in the NekRS mesh,

$var element = document.getElementById("moose-equation-12476198-0b4f-4a87-b54a-741698d1d055");katex.render("p=\\int_{\\Gamma}-k\\nabla T\\cdot\\hat{n}\\ d\\Gamma", element, {displayMode:true,throwOnError:false});$

where $var element = document.getElementById("moose-equation-ecca7571-f4ac-4498-a8c5-21481d890bf4");katex.render("p", element, {displayMode:false,throwOnError:false});$ is the value of the postprocessor, $var element = document.getElementById("moose-equation-620cc1f0-e1bb-4650-ba39-05e3bdbd58dc");katex.render("\\Gamma", element, {displayMode:false,throwOnError:false});$ is the boundary of the NekRS mesh, $var element = document.getElementById("moose-equation-c8b638f8-134b-4eed-a53b-e173e4926423");katex.render("k", element, {displayMode:false,throwOnError:false});$ is the fluid thermal conductivity, $var element = document.getElementById("moose-equation-00ec8db8-93e5-4cf9-b47e-330d46b96f48");katex.render("T", element, {displayMode:false,throwOnError:false});$ is the fluid temperature, and $var element = document.getElementById("moose-equation-12d08cfc-8502-4146-9db2-eacf83b7269a");katex.render("\\hat{n}", element, {displayMode:false,throwOnError:false});$ is the surface unit normal.

The boundaries over which to compute this postprocessor in the NekRS mesh are specified with the boundary parameter; these boundaries are the sidesets in NekRS's mesh (i.e. the .re2 file). You can specify more than one boundary, with syntax such as boundary = '1 2'. To be clear, this postprocessor is not evaluated on the NekRSMesh mesh mirror, but instead on the mesh actually used for computation in NekRS.

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.

Example Input Syntax

As an example, the pin_flux_in_nek and duct_flux_in_nek postprocessors below will evaluate the heat flux over two different boundaries in NekRS's mesh.

[Postprocessors]
  [pin_flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '1'
  []
  [duct_flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '2'
  []
  [max_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
[]

Input Parameters

boundaryBoundary ID(s) for which to compute the postprocessor
C++ Type:std::vector<int>
Controllable:No
Description:Boundary ID(s) for which to compute the postprocessor

Required Parameters

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, TRANSFER
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.
meshallNekRS mesh to compute postprocessor on
Default:all
C++ Type:MooseEnum
Options:fluid, solid, all
Controllable:No
Description:NekRS mesh to compute postprocessor on
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.

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
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
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/fhr_reflector/cht/nek.i)
(test/tests/cht/sfr_pincell/nek_vpp.i)
(test/tests/postprocessors/nek_heat_flux_integral/nek.i)
(test/tests/conduction/identical_volume/cube/nek.i)
(test/tests/conduction/boundary_and_volume/prism/nek.i)
(test/tests/cht/nondimensional/nek_exact.i)
(test/tests/nek_standalone/ethier/nek.i)
(test/tests/cht/pebble/nek.i)
(test/tests/nek_standalone/conj_ht/nek.i)
(test/tests/conduction/identical_interface/pyramid/nek.i)
(test/tests/conduction/boundary_and_volume/prism/nek_exact.i)
(tutorials/fhr_reflector/conduction/nek.i)
(tutorials/gas_compact_cht/nek.i)
(tutorials/sfr_7pin/nek.i)
(tutorials/sfr_7pin/nek_vpp.i)
(test/tests/cht/nondimensional/nek.i)
(test/tests/cht/sfr_pincell/nek.i)
(test/tests/cht/pebble/shift/nek.i)

(tutorials/sfr_7pin/nek.i)

[Mesh]
  type = NekRSMesh
  boundary = '1 2'
[]

[Problem]
  type = NekRSProblem
  casename = 'sfr_7pin'
  synchronization_interval = parent_app
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

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

[Postprocessors]
  [pin_flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '1'
  []
  [duct_flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '2'
  []
  [max_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
[]

(tutorials/fhr_reflector/cht/nek.i)

fluid_solid_interface = '1 2 7'

[Mesh]
  type = NekRSMesh
  boundary = ${fluid_solid_interface}
  scaling = 0.006
[]

[Problem]
  type = NekRSProblem
  casename = 'fluid'

  nondimensional = true
  U_ref = 0.0575
  T_ref = 923.15
  dT_ref = 10.0
  L_ref = 0.006
  rho_0 = 1962.13
  Cp_0 = 2416.0
[]

[Executioner]
  type = Transient
  timestep_tolerance = 1e-9

  [./TimeStepper]
    type = NekTimeStepper
  [../]
[]

[Outputs]
  exodus = true
[]

[Postprocessors]
  [boundary_flux]
    type = NekHeatFluxIntegral
    boundary = ${fluid_solid_interface}
  []
  [max_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
  [pressure_in]
    type = NekSideAverage
    field = pressure
    boundary = '5'
  []
  [mdot_in]
    type = NekMassFluxWeightedSideIntegral
    field = unity
    boundary = '5'
  []
  [mdot_out]
    type = NekMassFluxWeightedSideIntegral
    field = unity
    boundary = '6'
  []
[]

(test/tests/cht/sfr_pincell/nek_vpp.i)

[Problem]
  type = NekRSProblem
  casename = 'sfr_pin'
  conserve_flux_by_sideset = true

  # we only technically need one scratch space slot for this problem,
  # so we can skip allocating extra
  n_usrwrk_slots = 1
[]

[Mesh]
  type = NekRSMesh
  boundary = '1'
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
  [nek_flux]
    type = NekHeatFluxIntegral
    boundary = '1'
  []
  [average_inlet_T]
    type = NekSideAverage
    field = temperature
    boundary = '3'
    execute_on = initial
  []
  [average_outlet_T]
    type = NekSideAverage
    field = temperature
    boundary = '4'
  []
  [dT]
    type = DifferencePostprocessor
    value1 = average_outlet_T
    value2 = average_inlet_T
  []
  [inlet_mdot]
    type = NekMassFluxWeightedSideIntegral
    field = unity
    boundary = '3'
    execute_on = initial
  []

  # postprocessors for comparing against non-dimensional version in ../nondimensional
  # --> uncomment in order to get the reference values that the nondimensional boundary coupling
  #     was verified against
  #
  # # side integral
  # [area_1]
  #   type = NekSideIntegral
  #   field = unity
  #   boundary = '1'
  # []
  # [pressure_1]
  #   type = NekSideIntegral
  #   field = pressure
  #   boundary = '1'
  # []
  # [temperature_1]
  #   type = NekSideIntegral
  #   field = temperature
  #   boundary = '1'
  # []

  # # side average
  # [avg_area_1]
  #   type = NekSideAverage
  #   field = unity
  #   boundary = '1'
  # []
  # [avg_pressure_1]
  #   type = NekSideAverage
  #   field = pressure
  #   boundary = '1'
  # []
  # [avg_temperature_1]
  #   type = NekSideAverage
  #   field = temperature
  #   boundary = '1'
  # []

  # # volume integral
  # [volume]
  #   type = NekVolumeIntegral
  #   field = unity
  # []
  # [pressure_vol]
  #   type = NekVolumeIntegral
  #   field = pressure
  # []
  # [temperature_vol]
  #   type = NekVolumeIntegral
  #   field = temperature
  # []

  # # volume average
  # [avg_volume]
  #   type = NekVolumeAverage
  #   field = unity
  # []
  # [avg_pressure_vol]
  #   type = NekVolumeAverage
  #   field = pressure
  # []
  # [avg_temperature_vol]
  #   type = NekVolumeAverage
  #   field = temperature
  # []

  # # heat flux integral
  # [nek_flux]
  #   type = NekHeatFluxIntegral
  #   boundary = '1'
  # []

  # # mass flux weighted integral
  # [inlet_mdot]
  #   type = NekMassFluxWeightedSideIntegral
  #   field = unity
  #   boundary = '3'
  #   execute_on = initial
  # []
  # [outlet_T]
  #   type = NekMassFluxWeightedSideIntegral
  #   field = temperature
  #   boundary = '4'
  # []
  # [inlet_P]
  #   type = NekMassFluxWeightedSideIntegral
  #   field = pressure
  #   boundary = '4'
  # []

  # # mass flux weighted integral
  # [inlet_mdot_avg]
  #   type = NekMassFluxWeightedSideAverage
  #   field = unity
  #   boundary = '3'
  #   execute_on = initial
  # []
  # [outlet_T_avg]
  #   type = NekMassFluxWeightedSideAverage
  #   field = temperature
  #   boundary = '4'
  # []
  # [inlet_P_avg]
  #   type = NekMassFluxWeightedSideAverage
  #   field = pressure
  #   boundary = '4'
  # []

  # # extreme value postprocessors - VOLUME
  # [max_T]
  #   type = NekVolumeExtremeValue
  #   field = temperature
  #   value_type = max
  # []
  # [min_T]
  #   type = NekVolumeExtremeValue
  #   field = temperature
  #   value_type = min
  # []
  # [max_p]
  #   type = NekVolumeExtremeValue
  #   field = pressure
  #   value_type = max
  # []
  # [min_p]
  #   type = NekVolumeExtremeValue
  #   field = pressure
  #   value_type = min
  # []
  # [max_1]
  #   type = NekVolumeExtremeValue
  #   field = unity
  #   value_type = max
  # []
  # [min_1]
  #   type = NekVolumeExtremeValue
  #   field = unity
  #   value_type = min
  # []

  # # extreme value postprocessors - SIDE
  # [max_T_out]
  #   type = NekSideExtremeValue
  #   field = temperature
  #   boundary = '4'
  #   value_type = max
  # []
  # [min_T_out]
  #   type = NekSideExtremeValue
  #   field = temperature
  #   boundary = '4'
  #   value_type = min
  # []
  # [max_p_in]
  #   type = NekSideExtremeValue
  #   field = pressure
  #   boundary = '3'
  #   value_type = max
  # []
  # [min_p_in]
  #   type = NekSideExtremeValue
  #   field = pressure
  #   boundary = '3'
  #   value_type = min
  # []
  # [max_1_in]
  #   type = NekSideExtremeValue
  #   field = unity
  #   boundary = '3'
  #   value_type = max
  # []
  # [min_1_in]
  #   type = NekSideExtremeValue
  #   field = unity
  #   boundary = '3'
  #   value_type = min
  # []
[]

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

  [screen]
    type = Console
    hide = 'average_inlet_T average_outlet_T'
  []
[]

(test/tests/postprocessors/nek_heat_flux_integral/nek.i)

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

[Mesh]
  type = NekRSMesh
  boundary = '1 2 3 4 5 6 7 8'
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  [out]
    type = CSV
    hide = 'flux_integral'
    execute_on = 'final'
  []
[]

[Postprocessors]
  [flux_side1]
    type = NekHeatFluxIntegral
    boundary = '1'
  []
  [flux_side2]
    type = NekHeatFluxIntegral
    boundary = '2'
  []
  [flux_side3]
    type = NekHeatFluxIntegral
    boundary = '3'
  []
  [flux_side4]
    type = NekHeatFluxIntegral
    boundary = '4'
  []
  [flux_side5]
    type = NekHeatFluxIntegral
    boundary = '5'
  []
  [flux_side6]
    type = NekHeatFluxIntegral
    boundary = '6'
  []
  [flux_side7]
    type = NekHeatFluxIntegral
    boundary = '7'
  []
  [flux_side8]
    type = NekHeatFluxIntegral
    boundary = '8'
  []
[]

(test/tests/conduction/identical_volume/cube/nek.i)

[Problem]
  type = NekRSProblem
  casename = 'cube'

  # we only technically need two scratch space slots for this problem,
  # (the first is reserved for heat flux, but ultimately not used in this
  # volume-only problem, while the second is reserved for the volumetric heat
  # source, which is actually used),
  # so we can skip allocating extra
  n_usrwrk_slots = 2
[]

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

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
  [flux_out]
    type = NekHeatFluxIntegral
    boundary = '1 2 3 4 5 6'
  []
  [max_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [avg_T_volume]
    type = NekVolumeIntegral
    field = temperature
  []
  [avg_T_back]
    type = NekSideAverage
    field = temperature
    boundary = '6'
  []
[]

[Outputs]
  exodus = true
  execute_on = 'final'

  # for this tests purposes, we only want to check temperature. This keeps the gold file smaller
  hide = 'heat_source'
[]

(test/tests/conduction/boundary_and_volume/prism/nek.i)

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

[Mesh]
  type = NekRSMesh
  volume = true
  boundary = '2'
  order = FIRST
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
  [max_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [avg_T_volume]
    type = NekVolumeAverage
    field = temperature
  []
  [heat_flux]
    type = NekHeatFluxIntegral
    boundary = '2'
  []
  [nek_min_1]
    type = NekSideExtremeValue
    field = temperature
    boundary = '3'
    value_type = min
  []
  [nek_min_2]
    type = NekSideExtremeValue
    field = temperature
    boundary = '4'
    value_type = min
  []
  [nek_min_3]
    type = NekSideExtremeValue
    field = temperature
    boundary = '5'
    value_type = min
  []
  [nek_min_4]
    type = NekSideExtremeValue
    field = temperature
    boundary = '6'
    value_type = min
  []
  [nek_max_1]
    type = NekSideExtremeValue
    field = temperature
    boundary = '3'
  []
  [nek_max_2]
    type = NekSideExtremeValue
    field = temperature
    boundary = '4'
  []
  [nek_max_3]
    type = NekSideExtremeValue
    field = temperature
    boundary = '5'
  []
  [nek_max_4]
    type = NekSideExtremeValue
    field = temperature
    boundary = '6'
  []
[]

[Outputs]
  exodus = true
  interval = 30

  hide = 'flux_integral source_integral'
[]

(test/tests/cht/nondimensional/nek_exact.i)

[Problem]
  type = NekRSProblem
  casename = 'sfr_pin'

  # This input is run in nondimensional form to verify that all the postprocessors
  # and data transfers in/out of nekRS are properly dimensionalized.
  nondimensional = true
  U_ref = 0.0950466
  T_ref = 628.15
  dT_ref = 50.0
  L_ref = 0.908e-2
  rho_0 = 834.5
  Cp_0 = 1228.0
[]

[Mesh]
  type = NekRSMesh
  boundary = '1'
  exact = true

  # nekRS runs in non-dimensional form, which means that we shrunk the mesh
  # from physical units of meters to our characteristic scale of 0.908e-2 m
  # (the pin pitch, arbitrarily chosen). That means that we must multiply
  # the nekRS mesh by 0.908e-2 to get back in units of meters that BISON is
  # running in.
  scaling = 0.908e-2
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
# pressure is not a reliable quantity to compare in a short, few-timestep regression test.
# This line can be uncommented for comparing with the dimensional version.
inactive = 'avg_pressure_1 avg_pressure_vol max_p max_p_in min_p_in pressure_1 pressure_vol'

  [synchronization_in]
    type = Receiver
  []

  # side integral
  [area_1]
    type = NekSideIntegral
    field = unity
    boundary = '1'
  []
  [pressure_1]
    type = NekSideIntegral
    field = pressure
    boundary = '1'
  []
  [temperature_1]
    type = NekSideIntegral
    field = temperature
    boundary = '1'
  []

  # side average
  [avg_area_1]
    type = NekSideAverage
    field = unity
    boundary = '1'
  []
  [avg_pressure_1]
    type = NekSideAverage
    field = pressure
    boundary = '1'
  []
  [avg_temperature_1]
    type = NekSideAverage
    field = temperature
    boundary = '1'
  []

  # volume integral
  [volume]
    type = NekVolumeIntegral
    field = unity
  []
  [pressure_vol]
    type = NekVolumeIntegral
    field = pressure
  []
  [temperature_vol]
    type = NekVolumeIntegral
    field = temperature
  []

  # volume average
  [avg_volume]
    type = NekVolumeAverage
    field = unity
  []
  [avg_pressure_vol]
    type = NekVolumeAverage
    field = pressure
  []
  [avg_temperature_vol]
    type = NekVolumeAverage
    field = temperature
  []

  # heat flux integral
  [nek_flux]
    type = NekHeatFluxIntegral
    boundary = '1'
  []

  # mass flux weighted integral
  [inlet_mdot]
    type = NekMassFluxWeightedSideIntegral
    field = unity
    boundary = '3'
    execute_on = initial
  []
  [outlet_T]
    type = NekMassFluxWeightedSideIntegral
    field = temperature
    boundary = '4'
  []
  [inlet_P]
    type = NekMassFluxWeightedSideIntegral
    field = pressure
    boundary = '4'
  []

  # mass flux weighted integral
  [inlet_mdot_avg]
    type = NekMassFluxWeightedSideAverage
    field = unity
    boundary = '3'
    execute_on = initial
  []
  [outlet_T_avg]
    type = NekMassFluxWeightedSideAverage
    field = temperature
    boundary = '4'
  []
  [inlet_P_avg]
    type = NekMassFluxWeightedSideAverage
    field = pressure
    boundary = '4'
  []

  # extreme value postprocessors - VOLUME
  [max_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
  [max_p]
    type = NekVolumeExtremeValue
    field = pressure
    value_type = max
  []
  [min_p]
    type = NekVolumeExtremeValue
    field = pressure
    value_type = min
  []
  [max_1]
    type = NekVolumeExtremeValue
    field = unity
    value_type = max
  []
  [min_1]
    type = NekVolumeExtremeValue
    field = unity
    value_type = min
  []

  # extreme value postprocessors - SIDE
  [max_T_out]
    type = NekSideExtremeValue
    field = temperature
    boundary = '4'
    value_type = max
  []
  [min_T_out]
    type = NekSideExtremeValue
    field = temperature
    boundary = '4'
    value_type = min
  []
  [max_p_in]
    type = NekSideExtremeValue
    field = pressure
    boundary = '3'
    value_type = max
  []
  [min_p_in]
    type = NekSideExtremeValue
    field = pressure
    boundary = '3'
    value_type = min
  []
  [max_1_in]
    type = NekSideExtremeValue
    field = unity
    boundary = '3'
    value_type = max
  []
  [min_1_in]
    type = NekSideExtremeValue
    field = unity
    boundary = '3'
    value_type = min
  []
[]

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

  [screen]
    type = Console
    hide = 'synchronization_in'
  []
[]

(test/tests/nek_standalone/ethier/nek.i)

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

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

  # We omit the non-dimensional settings here in order to just extract the
  # non-dimensional solution as-is, without dimensionalizing it.
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
  [heat_flux]
    type = NekHeatFluxIntegral
    boundary = '1'
  []

  # These postprocessors are just used to verify correct extraction of the
  # NekRS solution, because we can directly compare against the values printed
  # to stdout by NekRS
  [max_Vx]
    type = NodalExtremeValue
    variable = vel_x
    value_type = max
  []
  [min_Vx]
    type = NodalExtremeValue
    variable = vel_x
    value_type = min
  []
  [max_Vy]
    type = NodalExtremeValue
    variable = vel_y
    value_type = max
  []
  [min_Vy]
    type = NodalExtremeValue
    variable = vel_y
    value_type = min
  []
  [max_Vz]
    type = NodalExtremeValue
    variable = vel_z
    value_type = max
  []
  [min_Vz]
    type = NodalExtremeValue
    variable = vel_z
    value_type = min
  []
  [max_p]
    type = NodalExtremeValue
    variable = P
    value_type = max
  []
  [min_p]
    type = NodalExtremeValue
    variable = P
    value_type = min
  []
  [max_T]
    type = NodalExtremeValue
    variable = temp
    value_type = max
  []
  [min_T]
    type = NodalExtremeValue
    variable = temp
    value_type = min
  []
[]

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

(test/tests/cht/pebble/nek.i)

[Mesh]
  type = NekRSMesh
  boundary = '1'

  # nekRS solves with a length scale of meters, but nek_master.i is currently solving
  # in terms of centimeters. Therefore, just for the sake of data transfers, we need to
  # scale NekRSMesh to centimeters.
  scaling = 100.0
[]

[Problem]
  type = NekRSProblem
  casename = 'onepebble2'
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

[Postprocessors]
  # This is the heat flux in the nekRS solution, i.e. it is not an integral
  # of nrs->usrwrk, instead this is directly an integral of k*grad(T)*hat(n).
  # So this should closely match 'flux_integral'
  [flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '1'
  []

  [max_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
[]

(test/tests/nek_standalone/conj_ht/nek.i)

[Mesh]
  type = NekRSMesh
  volume = true
[]

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

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
 [Area_BC3_flow]
   type = NekSideIntegral
   boundary = '3'
   field = unity
   mesh = 'fluid'
 []
 [Area_BC3_all]
   type = NekSideIntegral
   boundary = '3'
   field = unity
   mesh = 'all'
 []
 [SideAverage_T_BC3_flow]
   type = NekSideAverage
   boundary = '3'
   field = temperature
   mesh = 'fluid'
 []
 [SideAverage_T_BC3_all]
   type = NekSideAverage
   boundary = '3'
   field = temperature
   mesh = 'all'
 []
 [HeatFluxIntegral_BC3_flow]
   type = NekHeatFluxIntegral
   boundary = '3'
   mesh = 'fluid'
 []
 [HeatFluxIntegral_BC3_all]
   type = NekHeatFluxIntegral
   boundary = '3'
   mesh = 'all'
 []
 [MassFlowRate_BC1_flow]
   type = NekMassFluxWeightedSideIntegral
   boundary = '1'
   field = unity
   mesh = 'fluid'
 []
 [MassFlowRate_BC1_all]
   type = NekMassFluxWeightedSideIntegral
   boundary = '1'
   field = unity
   mesh = 'all'
 []
 [MflowAvgTemp_BC2_flow]
   type = NekMassFluxWeightedSideAverage
   boundary = '2'
   field = temperature
   mesh = 'fluid'
 []
 [MflowAvgTemp_BC2_all]
   type = NekMassFluxWeightedSideAverage
   boundary = '2'
   field = temperature
   mesh = 'all'
 []
 [Reynolds_BC1_flow]
   type = ReynoldsNumber
   boundary = '1'
   L_ref = 0.5
   mesh = 'fluid'
 []
 [Reynolds_BC1_all]
   type = ReynoldsNumber
   boundary = '1'
   L_ref = 0.5
   mesh = 'all'
 []
 [Peclet_BC1_flow]
   type = PecletNumber
   boundary = '1'
   L_ref = 0.5
   mesh = 'fluid'
 []
 [Peclet_BC1_all]
   type = PecletNumber
   boundary = '1'
   L_ref = 0.5
   mesh = 'all'
 []
#
# Volume post processors
#
 [Vol_flow]
   type = NekVolumeIntegral
   field = unity
   mesh = 'fluid'
 []
 [Vol_all]
   type = NekVolumeIntegral
   field = unity
   mesh = 'all'
 []
 [maxVol_T_flow]
   type = NekVolumeExtremeValue
   field = temperature
   value_type = max
   mesh = 'fluid'
 []
 [maxVol_T_all]
   type = NekVolumeExtremeValue
   field = temperature
   value_type = max
   mesh = 'all'
 []
 [avgVol_T_flow]
   type = NekVolumeAverage
   field = temperature
   mesh = 'fluid'
 []
 [avgVol_T_all]
   type = NekVolumeAverage
   field = temperature
   mesh = 'all'
 []
[]

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

(test/tests/conduction/identical_interface/pyramid/nek.i)

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

[Mesh]
  type = NekRSMesh
  boundary = '2'
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
  [max_temp_nek]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_temp_nek]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
  [heat_flux]
    type = NekHeatFluxIntegral
    boundary = '2'
  []
[]

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

(test/tests/conduction/boundary_and_volume/prism/nek_exact.i)

[Problem]
  type = NekRSProblem
  casename = 'pyramid_low'
  usrwrk_output = '0 1'
  usrwrk_output_prefix = 'flx src'
[]

[Mesh]
  type = NekRSMesh
  volume = true
  boundary = '2'
  order = FIRST
  exact = true
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
  [max_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [avg_T_volume]
    type = NekVolumeAverage
    field = temperature
  []
  [heat_flux]
    type = NekHeatFluxIntegral
    boundary = '2'
  []
  [nek_min_1]
    type = NekSideExtremeValue
    field = temperature
    boundary = '3'
    value_type = min
  []
  [nek_min_2]
    type = NekSideExtremeValue
    field = temperature
    boundary = '4'
    value_type = min
  []
  [nek_min_3]
    type = NekSideExtremeValue
    field = temperature
    boundary = '5'
    value_type = min
  []
  [nek_min_4]
    type = NekSideExtremeValue
    field = temperature
    boundary = '6'
    value_type = min
  []
  [nek_max_1]
    type = NekSideExtremeValue
    field = temperature
    boundary = '3'
  []
  [nek_max_2]
    type = NekSideExtremeValue
    field = temperature
    boundary = '4'
  []
  [nek_max_3]
    type = NekSideExtremeValue
    field = temperature
    boundary = '5'
  []
  [nek_max_4]
    type = NekSideExtremeValue
    field = temperature
    boundary = '6'
  []
[]

[Outputs]
  exodus = true
  interval = 30

  hide = 'flux_integral source_integral'
[]

(tutorials/fhr_reflector/conduction/nek.i)

fluid_solid_interface = '1 2 7'

[Mesh]
  type = NekRSMesh
  boundary = ${fluid_solid_interface}
  scaling = 0.006
[]

[Problem]
  type = NekRSProblem
  casename = 'fluid'

  nondimensional = true
  U_ref = 0.0575
  T_ref = 923.15
  dT_ref = 10.0
  L_ref = 0.006
  rho_0 = 1962.13
  Cp_0 = 2416.0
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
[]

[Postprocessors]
  [boundary_flux]
    type = NekHeatFluxIntegral
    boundary = ${fluid_solid_interface}
  []
  [max_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
[]

(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
  []
[]

(tutorials/sfr_7pin/nek.i)

[Mesh]
  type = NekRSMesh
  boundary = '1 2'
[]

[Problem]
  type = NekRSProblem
  casename = 'sfr_7pin'
  synchronization_interval = parent_app
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

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

[Postprocessors]
  [pin_flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '1'
  []
  [duct_flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '2'
  []
  [max_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
[]

(tutorials/sfr_7pin/nek_vpp.i)

[Mesh]
  type = NekRSMesh
  boundary = '1 2'
[]

[Problem]
  type = NekRSProblem
  casename = 'sfr_7pin'
  conserve_flux_by_sideset = true
  synchronization_interval = parent_app
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

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

[Postprocessors]
  [pin_flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '1'
  []
  [duct_flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '2'
  []
  [max_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
[]

(test/tests/cht/nondimensional/nek.i)

[Problem]
  type = NekRSProblem
  casename = 'sfr_pin'

  # This input is run in nondimensional form to verify that all the postprocessors
  # and data transfers in/out of nekRS are properly dimensionalized.
  nondimensional = true
  U_ref = 0.0950466
  T_ref = 628.15
  dT_ref = 50.0
  L_ref = 0.908e-2
  rho_0 = 834.5
  Cp_0 = 1228.0
[]

[Mesh]
  type = NekRSMesh
  boundary = '1'

  # nekRS runs in non-dimensional form, which means that we shrunk the mesh
  # from physical units of meters to our characteristic scale of 0.908e-2 m
  # (the pin pitch, arbitrarily chosen). That means that we must multiply
  # the nekRS mesh by 0.908e-2 to get back in units of meters that BISON is
  # running in.
  scaling = 0.908e-2
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
  [synchronization_in]
    type = Receiver
  []

  # side integral
  [area_1]
    type = NekSideIntegral
    field = unity
    boundary = '1'
  []
  [pressure_1]
    type = NekSideIntegral
    field = pressure
    boundary = '1'
  []
  [temperature_1]
    type = NekSideIntegral
    field = temperature
    boundary = '1'
  []

  # side average
  [avg_area_1]
    type = NekSideAverage
    field = unity
    boundary = '1'
  []
  [avg_pressure_1]
    type = NekSideAverage
    field = pressure
    boundary = '1'
  []
  [avg_temperature_1]
    type = NekSideAverage
    field = temperature
    boundary = '1'
  []

  # volume integral
  [volume]
    type = NekVolumeIntegral
    field = unity
  []
  [pressure_vol]
    type = NekVolumeIntegral
    field = pressure
  []
  [temperature_vol]
    type = NekVolumeIntegral
    field = temperature
  []

  # volume average
  [avg_volume]
    type = NekVolumeAverage
    field = unity
  []
  [avg_pressure_vol]
    type = NekVolumeAverage
    field = pressure
  []
  [avg_temperature_vol]
    type = NekVolumeAverage
    field = temperature
  []

  # heat flux integral
  [nek_flux]
    type = NekHeatFluxIntegral
    boundary = '1'
  []

  # mass flux weighted integral
  [inlet_mdot]
    type = NekMassFluxWeightedSideIntegral
    field = unity
    boundary = '3'
    execute_on = initial
  []
  [outlet_T]
    type = NekMassFluxWeightedSideIntegral
    field = temperature
    boundary = '4'
  []
  [inlet_P]
    type = NekMassFluxWeightedSideIntegral
    field = pressure
    boundary = '4'
  []

  # mass flux weighted integral
  [inlet_mdot_avg]
    type = NekMassFluxWeightedSideAverage
    field = unity
    boundary = '3'
    execute_on = initial
  []
  [outlet_T_avg]
    type = NekMassFluxWeightedSideAverage
    field = temperature
    boundary = '4'
  []
  [inlet_P_avg]
    type = NekMassFluxWeightedSideAverage
    field = pressure
    boundary = '4'
  []

  # extreme value postprocessors - VOLUME
  [max_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
  [max_p]
    type = NekVolumeExtremeValue
    field = pressure
    value_type = max
  []
  [min_p]
    type = NekVolumeExtremeValue
    field = pressure
    value_type = min
  []
  [max_1]
    type = NekVolumeExtremeValue
    field = unity
    value_type = max
  []
  [min_1]
    type = NekVolumeExtremeValue
    field = unity
    value_type = min
  []

  # extreme value postprocessors - SIDE
  [max_T_out]
    type = NekSideExtremeValue
    field = temperature
    boundary = '4'
    value_type = max
  []
  [min_T_out]
    type = NekSideExtremeValue
    field = temperature
    boundary = '4'
    value_type = min
  []
  [max_p_in]
    type = NekSideExtremeValue
    field = pressure
    boundary = '3'
    value_type = max
  []
  [min_p_in]
    type = NekSideExtremeValue
    field = pressure
    boundary = '3'
    value_type = min
  []
  [max_1_in]
    type = NekSideExtremeValue
    field = unity
    boundary = '3'
    value_type = max
  []
  [min_1_in]
    type = NekSideExtremeValue
    field = unity
    boundary = '3'
    value_type = min
  []
[]

[Outputs]
  exodus = true
  execute_on = 'final'

  [screen]
    type = Console
    hide = 'synchronization_in'
  []
[]

(test/tests/cht/sfr_pincell/nek.i)

[Problem]
  type = NekRSProblem
  casename = 'sfr_pin'
  synchronization_interval = parent_app

  # we only technically need one scratch space slot for this problem,
  # so we can skip allocating extra
  n_usrwrk_slots = 1
[]

[Mesh]
  type = NekRSMesh
  boundary = '1'
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Postprocessors]
  [nek_flux]
    type = NekHeatFluxIntegral
    boundary = '1'
  []
  [average_inlet_T]
    type = NekSideAverage
    field = temperature
    boundary = '3'
    execute_on = initial
  []
  [average_outlet_T]
    type = NekSideAverage
    field = temperature
    boundary = '4'
  []
  [dT]
    type = DifferencePostprocessor
    value1 = average_outlet_T
    value2 = average_inlet_T
  []
  [inlet_mdot]
    type = NekMassFluxWeightedSideIntegral
    field = unity
    boundary = '3'
    execute_on = initial
  []

  # postprocessors for comparing against non-dimensional version in ../nondimensional
  # --> uncomment in order to get the reference values that the nondimensional boundary coupling
  #     was verified against
  #
  # # side integral
  # [area_1]
  #   type = NekSideIntegral
  #   field = unity
  #   boundary = '1'
  # []
  # [pressure_1]
  #   type = NekSideIntegral
  #   field = pressure
  #   boundary = '1'
  # []
  # [temperature_1]
  #   type = NekSideIntegral
  #   field = temperature
  #   boundary = '1'
  # []

  # # side average
  # [avg_area_1]
  #   type = NekSideAverage
  #   field = unity
  #   boundary = '1'
  # []
  # [avg_pressure_1]
  #   type = NekSideAverage
  #   field = pressure
  #   boundary = '1'
  # []
  # [avg_temperature_1]
  #   type = NekSideAverage
  #   field = temperature
  #   boundary = '1'
  # []

  # # volume integral
  # [volume]
  #   type = NekVolumeIntegral
  #   field = unity
  # []
  # [pressure_vol]
  #   type = NekVolumeIntegral
  #   field = pressure
  # []
  # [temperature_vol]
  #   type = NekVolumeIntegral
  #   field = temperature
  # []

  # # volume average
  # [avg_volume]
  #   type = NekVolumeAverage
  #   field = unity
  # []
  # [avg_pressure_vol]
  #   type = NekVolumeAverage
  #   field = pressure
  # []
  # [avg_temperature_vol]
  #   type = NekVolumeAverage
  #   field = temperature
  # []

  # # heat flux integral
  # [nek_flux]
  #   type = NekHeatFluxIntegral
  #   boundary = '1'
  # []

  # # mass flux weighted integral
  # [inlet_mdot]
  #   type = NekMassFluxWeightedSideIntegral
  #   field = unity
  #   boundary = '3'
  #   execute_on = initial
  # []
  # [outlet_T]
  #   type = NekMassFluxWeightedSideIntegral
  #   field = temperature
  #   boundary = '4'
  # []
  # [inlet_P]
  #   type = NekMassFluxWeightedSideIntegral
  #   field = pressure
  #   boundary = '4'
  # []

  # # mass flux weighted integral
  # [inlet_mdot_avg]
  #   type = NekMassFluxWeightedSideAverage
  #   field = unity
  #   boundary = '3'
  #   execute_on = initial
  # []
  # [outlet_T_avg]
  #   type = NekMassFluxWeightedSideAverage
  #   field = temperature
  #   boundary = '4'
  # []
  # [inlet_P_avg]
  #   type = NekMassFluxWeightedSideAverage
  #   field = pressure
  #   boundary = '4'
  # []

  # # extreme value postprocessors - VOLUME
  # [max_T]
  #   type = NekVolumeExtremeValue
  #   field = temperature
  #   value_type = max
  # []
  # [min_T]
  #   type = NekVolumeExtremeValue
  #   field = temperature
  #   value_type = min
  # []
  # [max_p]
  #   type = NekVolumeExtremeValue
  #   field = pressure
  #   value_type = max
  # []
  # [min_p]
  #   type = NekVolumeExtremeValue
  #   field = pressure
  #   value_type = min
  # []
  # [max_1]
  #   type = NekVolumeExtremeValue
  #   field = unity
  #   value_type = max
  # []
  # [min_1]
  #   type = NekVolumeExtremeValue
  #   field = unity
  #   value_type = min
  # []

  # # extreme value postprocessors - SIDE
  # [max_T_out]
  #   type = NekSideExtremeValue
  #   field = temperature
  #   boundary = '4'
  #   value_type = max
  # []
  # [min_T_out]
  #   type = NekSideExtremeValue
  #   field = temperature
  #   boundary = '4'
  #   value_type = min
  # []
  # [max_p_in]
  #   type = NekSideExtremeValue
  #   field = pressure
  #   boundary = '3'
  #   value_type = max
  # []
  # [min_p_in]
  #   type = NekSideExtremeValue
  #   field = pressure
  #   boundary = '3'
  #   value_type = min
  # []
  # [max_1_in]
  #   type = NekSideExtremeValue
  #   field = unity
  #   boundary = '3'
  #   value_type = max
  # []
  # [min_1_in]
  #   type = NekSideExtremeValue
  #   field = unity
  #   boundary = '3'
  #   value_type = min
  # []
[]

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

  [screen]
    type = Console
    hide = 'average_inlet_T average_outlet_T transfer_in'
  []
[]

(test/tests/cht/pebble/shift/nek.i)

[Mesh]
  type = NekRSMesh
  boundary = '1'
  scaling = 100.0
[]

[Problem]
  type = NekRSProblem
  casename = 'onepebble2'
  first_reserved_usrwrk_slot = 1
[]

[Executioner]
  type = Transient

  [TimeStepper]
    type = NekTimeStepper
  []
[]

[Outputs]
  exodus = true
  csv = true
[]

[Postprocessors]
  [flux_in_nek]
    type = NekHeatFluxIntegral
    boundary = '1'
  []
  [max_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = max
  []
  [min_nek_T]
    type = NekVolumeExtremeValue
    field = temperature
    value_type = min
  []
[]

Description
Example Input Syntax
Input Parameters
Input Files