- boundaryThe list of boundary IDs from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundary IDs from the mesh where this object applies
- cpThe specific heat at constant pressure. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:The specific heat at constant pressure. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- muDynamic viscosity. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:Dynamic viscosity. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- rhoDensity. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:Density. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- uThe velocity in the x direction. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:The velocity in the x direction. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- variableThe name of the variable that this boundary condition applies to
C++ Type:LinearVariableName
Unit:(no unit assumed)
Controllable:No
Description:The name of the variable that this boundary condition applies to
LinearFVTemperatureWallFunctionBC
Implements a wall function boundary condition for the effective thermal conductivity at the wall for the linear finite volume discretization.
This boundary condition computes an effective wall thermal conductivity used to represent turbulent heat transfer near solid boundaries without fully resolving the thermal boundary layer. As in LinearFVTurbulentViscosityWallFunctionBC, the near-wall behavior is parameterized in terms of the non-dimensional wall distance and the friction velocity , using the selected "wall_treatment".
The wall heat flux is modeled through an effective conductivity, , such that
where:
is the wall heat flux,
is the effective wall thermal conductivity returned by this boundary condition,
is the temperature at the centroid of the fluid near-wall cell,
is the wall temperature,
is the wall-normal distance from the wall face to the centroid of the near-wall cell.
The wall function computes this effective conductivity as
where:
is the density
is the specific heat capacity
is the friction velocity
is the dimensionless temperature
The molecular Prandtl number is defined as
where:
is the molecular dynamic viscosity
is the molecular thermal conductivity
The turbulent Prandtl number is provided through the material property "Pr_t". As in the turbulent viscosity wall function, four different formulations are supported to compute and , as defined by the "wall_treatment".
The same recommendations about mesh design and wall-normal spacing given in LinearFVTurbulentViscosityWallFunctionBC apply here as well.
Thermal wall-function formulation
Once and are computed, the thermal wall function evaluates the dimensionless temperature using the thermal sublayer thickness , obtained from a fixed point solve through NS::findYplusThermal, which is dependent on and .
The thermal sublayer thickness is then used as the parameter to discern whether to employ laminar sublayer thermal wall functions or turbulent logarithmic layer thermal wall functions:
with
where:
is the von Karman constant,
is the wall-function log law offset constant,
is the Jayatilleke temperature offset
The returned boundary value is then
This wall function is formulated for molecular Prandtl numbers of order 1 or greater, as is typical for gases and most liquids. For low-Prandtl-number fluids, such as liquid metals, can grow well past the validity range of the underlying equilibrium velocity wall function (i.e. into or beyond the logarithmic layer), making the sub-laminar/logarithmic switch and the resulting unreliable. A dedicated low-Prandtl-number thermal wall treatment is recommended for such fluids.
Input Parameters
- C_mu0.09Coupled turbulent kinetic energy closure.
Default:0.09
C++ Type:Real
Unit:(no unit assumed)
Controllable:No
Description:Coupled turbulent kinetic energy closure.
- Pr_t0.7The turbulent Prandtl number. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
Default:0.7
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:The turbulent Prandtl number. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- kThe thermal conductivity. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:The thermal conductivity. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- tkeThe turbulent kinetic energy. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:The turbulent kinetic energy. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- vThe velocity in the y direction. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:The velocity in the y direction. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- wThe velocity in the z direction. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
C++ Type:MooseFunctorName
Unit:(no unit assumed)
Controllable:No
Description:The velocity in the z direction. A functor is any of the following: a variable, a functor material property, a function, a postprocessor or a number.
- wall_treatmentneqThe method used for computing the wall functions
Default:neq
C++ Type:MooseEnum
Controllable:No
Description:The method used for computing the wall functions
Optional Parameters
- absolute_value_vector_tagsThe tags for the vectors this residual object should fill with the absolute value of the residual contribution
C++ Type:std::vector<TagName>
Controllable:No
Description:The tags for the vectors this residual object should fill with the absolute value of the residual contribution
- extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector<TagName>
Controllable:No
Description:The extra tags for the matrices this Kernel should fill
- extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector<TagName>
Controllable:No
Description:The extra tags for the vectors this Kernel should fill
- matrix_onlyFalseWhether this object is only doing assembly to matrices (no vectors)
Default:False
C++ Type:bool
Controllable:No
Description:Whether this object is only doing assembly to matrices (no vectors)
- matrix_tagssystemThe tag for the matrices this Kernel should fill
Default:system
C++ Type:MultiMooseEnum
Controllable:No
Description:The tag for the matrices this Kernel should fill
- vector_tagsrhsThe tag for the vectors this Kernel should fill
Default:rhs
C++ Type:MultiMooseEnum
Controllable:No
Description:The tag for the vectors this Kernel should fill
Contribution To Tagged Field Data Parameters
- control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Controllable:No
Description:Adds user-defined labels for accessing object parameters via control logic.
- enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:Yes
Description:Set the enabled status of the MooseObject.
- implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Controllable:No
Description:Determines whether this object is calculated using an implicit or explicit form
- search_methodnearest_node_connected_sidesChoice of search algorithm. All options begin by finding the nearest node in the primary boundary to a query point in the secondary boundary. In the default nearest_node_connected_sides algorithm, primary boundary elements are searched iff that nearest node is one of their nodes. This is fast to determine via a pregenerated node-to-elem map and is robust on conforming meshes. In the optional all_proximate_sides algorithm, primary boundary elements are searched iff they touch that nearest node, even if they are not topologically connected to it. This is more CPU-intensive but is necessary for robustness on any boundary surfaces which has disconnections (such as Flex IGA meshes) or non-conformity (such as hanging nodes in adaptively h-refined meshes).
Default:nearest_node_connected_sides
C++ Type:MooseEnum
Controllable:No
Description:Choice of search algorithm. All options begin by finding the nearest node in the primary boundary to a query point in the secondary boundary. In the default nearest_node_connected_sides algorithm, primary boundary elements are searched iff that nearest node is one of their nodes. This is fast to determine via a pregenerated node-to-elem map and is robust on conforming meshes. In the optional all_proximate_sides algorithm, primary boundary elements are searched iff they touch that nearest node, even if they are not topologically connected to it. This is more CPU-intensive but is necessary for robustness on any boundary surfaces which has disconnections (such as Flex IGA meshes) or non-conformity (such as hanging nodes in adaptively h-refined meshes).