## Information and Tools

Boundary condition for radiative heat exchange with a cylinderwhere the boundary is approximated as a cylinder as well.

This boundary condition computes the radiative heat flux from the boundary to an infinite cylinder completely surrounding it. The boundary itself is assumed to be a cylinder that is concentric to the enclosing cylinder. Geometry information is provided by boundary_radius and cylinder_radius parameters. The mesh is not queried for geometric information.

[./radiative_bc]
boundary = right
variable = temp
boundary_emissivity = 0.2
cylinder_emissivity = 0.7
Tinfinity = 500
[../]


## Input Parameters

• variableThe name of the variable that this boundary condition applies to

C++ Type:NonlinearVariableName

Options:

Description:The name of the variable that this boundary condition applies to

C++ Type:double

Options:

Description:Radius of the cylinder on the outside of the boundary.

• boundaryThe list of boundary IDs from the mesh where this boundary condition applies

C++ Type:std::vector

Options:

Description:The list of boundary IDs from the mesh where this boundary condition applies

C++ Type:double

Options:

Description:Radius of the boundary approximated as cylinder.

### Required Parameters

• Tinfinity0Temperature of the body in radiative heat transfer.

Default:0

C++ Type:FunctionName

Options:

Description:Temperature of the body in radiative heat transfer.

• cylinder_emissivity1Emissivity of the cylinder in radiative heat transfer with the boundary.

Default:1

C++ Type:double

Options:

Description:Emissivity of the cylinder in radiative heat transfer with the boundary.

• stefan_boltzmann_constant5.67037e-08The Stefan-Boltzmann constant.

Default:5.67037e-08

C++ Type:double

Options:

Description:The Stefan-Boltzmann constant.

• displacementsThe displacements

C++ Type:std::vector

Options:

Description:The displacements

• boundary_emissivity1Emissivity of the boundary.

Default:1

C++ Type:double

Options:

Description:Emissivity of the boundary.

### Optional Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

Description:Set the enabled status of the MooseObject.

• save_inThe name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

C++ Type:std::vector

Options:

Description:The name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

• 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

Options:

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.

• control_tagsAdds user-defined labels for accessing object parameters via control logic.

C++ Type:std::vector

Options:

Description:Adds user-defined labels for accessing object parameters via control logic.

• seed0The seed for the master random number generator

Default:0

C++ Type:unsigned int

Options:

Description:The seed for the master random number generator

• diag_save_inThe name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

C++ Type:std::vector

Options:

Description:The name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

• implicitTrueDetermines whether this object is calculated using an implicit or explicit form

Default:True

C++ Type:bool

Options:

Description:Determines whether this object is calculated using an implicit or explicit form

• vector_tagsnontimeThe tag for the vectors this Kernel should fill

Default:nontime

C++ Type:MultiMooseEnum

Options:nontime time

Description:The tag for the vectors this Kernel should fill

• extra_vector_tagsThe extra tags for the vectors this Kernel should fill

C++ Type:std::vector

Options:

Description:The extra tags for the vectors this Kernel should fill

• matrix_tagssystemThe tag for the matrices this Kernel should fill

Default:system

C++ Type:MultiMooseEnum

Options:nontime system

Description:The tag for the matrices this Kernel should fill

• extra_matrix_tagsThe extra tags for the matrices this Kernel should fill

C++ Type:std::vector

Options:

Description:The extra tags for the matrices this Kernel should fill