Radiation Field Functions Reference

The following primitive field functions are made available to the simulation when a radiation transfer model (S2S, SPMC, or DOM) is used.


Boundary Emissivity	The gray emissivity at the boundary. Only available for gray radiation.
Boundary Emissivity of <band-name>	The spectral emissivity at the boundary for band <band-name>. Only available for spectral radiation (multiband).
Boundary Emissivity on External Side	The gray emissivity at the surface for the outward-facing side. This field function is only available when the Radiation Transfer Option is set to External or Internal and External.
Boundary Emissivity on External Side of <band-name>	The gray emissivity at the surface of the outward-facing side for band <band-name>. This field function is only available when the Radiation Transfer Option is set to External or Internal and External.
Boundary Irradiation	The irradiation at the boundary. The irradiation is the radiative heat flux incident on a surface. This property is a full-spectrum quantity. For spectral radiation (multiband), it includes contributions from all wavelengths (bands).
Boundary Irradiation of <band-name>	The irradiation for band <band-name>. Only available for spectral radiation (multiband).
Boundary Radiation Heat Flux	The net radiative heat flux to the boundary (absorption minus emission). A positive value indicates a net absorption by the boundary. This property is a full-spectrum quantity. For spectral radiation (multiband), it includes contributions from all wavelengths (bands).
Boundary Radiation Heat Flux of <band-name>	The net radiative heat flux to the boundary (absorption minus emission) for band <band-name>.
Boundary Radiosity	The radiosity at the boundary. The radiosity is essentially the outgoing radiative heat flux from a surface, and consists of local emission and the reflected component of the irradiation. This property is a full-spectrum quantity. For spectral radiation (multiband), it includes contributions from all wavelengths (bands).
Boundary Radiosity of <band-name>	The radiosity for band <band-name>. Only available for spectral radiation (multiband).
Boundary Reflection Specularity	The fraction of total reflectivity which is specular in nature.
Boundary Reflection Specularity of <band-name>	The fraction of total reflectivity for band <band-name> which is specular in nature.
Boundary Reflection Specularity on External Side	The fraction of total reflectivity on the surface for the outward-facing side which is specular in nature. This field function is only available when the Radiation Transfer Option is set to External or Internal and External.
Boundary Reflection Specularity on External Side of <band-name>	The fraction of total reflectivity for band <band-name> on the surface for the outward-facing side which is specular in nature. This field function is only available when the Radiation Transfer Option is set to External or Internal and External.
Boundary Reflectivity	The gray reflectivity at the boundary. Only available for gray radiation.
Boundary Reflectivity of <band-name>	The spectral reflectivity at the boundary for band <band-name>. Only available for spectral radiation (multiband).
Boundary Reflectivity on External Side	The gray reflectivity at the surface of the outward-facing side. Only available for gray radiation. This field function is only available when the Radiation Transfer Option is set to External or Internal and External.
Boundary Reflectivity on External Side of <band-name>	The gray reflectivity at the surface of the outward-facing side for band <band-name>. Only available for spectral radiation (multiband). This field function is only available when the Radiation Transfer Option is set to External or Internal and External.
Boundary Transmissivity	The gray transmissivity at the boundary. Only available for gray radiation.
Boundary Transmissivity of <band-name>	The spectral transmissivity at the boundary for band <band-name>. Only available for spectral radiation (multiband).
Total Emissivity	The blackbody-emissive-power-weighted emissivity at the boundary. For gray radiation, this property is simply the gray surface emissivity. For spectral radiation, this property is defined as: $ε_{t o t a l} = (\sum_{i \in b a n d s}^{} n_{i}^{2} ε_{i} E_{b, i}) / (\sum_{i \in b a n d s}^{} E_{b, i})$ where $n$ is the index of refraction, $E_{b}$ is the blackbody emissive power and the subscript i denotes the band.
User-specified Diffuse Flux	The user-defined value of diffuse radiation flux specified on a boundary. This flux models non-thermal (non-Planck) emission coming out of a boundary. It does not affect the originating boundary thermally but can affect other boundaries thermally.
User-specified Diffuse Flux of <band-name>	The user-defined value of diffuse radiation flux for band <band-name> specified on a boundary. This flux models non-thermal (non-Planck) emission coming out of a boundary. It does not affect the originating boundary thermally but can affect other boundaries thermally.

The following primitive field functions are additionally made available when the Surface-to-Surface (S2S) or Surface Photon Monte Carlo (SPMC) Radiation model is activated.


Boundary Irradiation on External Side	The irradiation of the external side of a boundary between the environment and an internal domain. Available only when the Radiation Transfer Option is set to External or Internal and External.
Boundary Irradiation on External Side of <band-name>	The irradiation of the external side of a boundary between the environment and an internal domain for band <band-name>. Available only when the Radiation Transfer Option is set to External or Internal and External.
Boundary Mean Radiant Temperature	The mean radiant temperature (MRT) at the boundary. See Mean Radiant Temperature (MRT).
Boundary Radiation Heat-Flux on External Side	The radiation heat-flux of the external side of a boundary between the environment and an internal domain. Available only when the Radiation Transfer Option is set to External or Internal and External.
Boundary Radiation Heat-Flux on External Side of <band-name>	The radiation heat-flux of the external side of a boundary between the environment and an internal domain for band <band-name>. Available only when the Radiation Transfer Option is set to External or Internal and External.
Boundary Radiosity on External Side	The radiosity of the external side of a boundary between the environment and an internal domain. Available only when the Radiation Transfer Option is set to External or Internal and External.
Boundary Radiosity on External Side of <band-name>	The radiosity of the external side of a boundary between the environment and an internal domain for band <band-name>. Available only when the Radiation Transfer Option is set to External or Internal and External.
Diffuse Solar Irradiation	The solar flux on the boundary from the surrounding environment. This quantity is only available for gray radiation when the Solar Loads model is activated.
Diffuse Solar Irradiation of <band-name>	The solar flux on the boundary from the surrounding environment for band <band-name>. This quantity is only available for spectral radiation (multiband) when the Solar Loads model is activated.
Diffuse Solar Irradiation on External Side	The solar flux from the surrounding environment for band <band-name> on the external side of a boundary. Available only when the Radiation Transfer Option is set to External or Internal and External.
Diffuse Solar Irradiation on External Side of <band-name>	The solar flux from the surrounding environment on the external side of a boundary. This quantity is only available for spectral radiation (multiband) when the Solar Loads model is activated, and with Radiation Transfer Option set to External or Internal and External.
Direct Solar Irradiation	The direct solar flux on the boundary. This quantity is only available for gray radiation when the Solar Loads model is activated.
Direct Solar Irradiation of <band-name>	The direct solar flux on the boundary for band <band-name>. This quantity is only available for spectral radiation (multiband) when the Solar Loads model is activated.
Direct Solar Irradiation on External Side	The direct solar flux on the external side of the boundary. This quantity is only available for gray radiation when the Solar Loads model is activated, and with Radiation Transfer Option set to External or Internal and External.
Direct Solar Irradiation on External Side of <band-name>	The direct solar flux on the external side of the boundary for band <band-name>. This quantity is only available for gray radiation when the Solar Loads model is activated, and with Radiation Transfer Option set to External or Internal and External.

The following primitive field functions are additionally made available when the Participating Media Radiation (DOM) model is activated.


Absorption Coefficient	The absorption coefficient for the media. For spectral radiation (multiband), each band has a separate variable which is differentiated by the band index, for example Absorption Coefficient 0 for the first band.
Incident Radiation	The zeroth angular moment of radiative intensity ( $G = \int_{4 π}^{} I d Ω$ ). This quantity is also proportionally related to the energy density ( $u_{e} = G / c$ where c is the speed of light) and to the mean intensity ( $\bar{I} = G / 4 π$ ). This property is a full-spectrum quantity. For spectral radiation (multiband), it includes contributions from all wavelengths (bands).
Particle Radiative Energy Source	The volumetric (integrated over dispersed media in a given cell) source due to radiative absorption and emission by dispersed media, such as particles (absorption by particles minus emission from particles). A positive value indicates net absorption by the dispersed media. This quantity is equal to the negative of the divergence of the radiative heat flux from dispersed media.
Radiative Absorption	The volumetric absorption by the media. This quantity is the absorption part of the Radiative Energy Source.
Radiative Energy Source	The volumetric source to the energy equation due to radiative absorption and emission (absorption minus emission). A positive value indicates net absorption by the media. This quantity is equal to the negative of the divergence of the radiative heat flux. This field function is available for continuous media only.
Radiative Intensity j	The radiative intensity for the $j$ th ordinate direction. For spectral radiation (multiband), this variable contains the intensity field as a full-spectrum quantity.
Refractive Index	The refractive index for the media. This quantity is only available for gray radiation when the Refraction (Gray) model is activated.
Refractive Index i	The refractive index for the media, of the $i$ th band. This quantity is only available for multiband thermal radiation when the Refraction (Multiband) model is activated.
Scattering Coefficient	The scattering coefficient for the media. For spectral radiation (multiband), each band has a separate variable which is differentiated by the band index, for example Scattering Coefficient 0 for the first band.
Total Absorption Coefficient	The blackbody-emissive-power-weighted absorption coefficient within the domain. For gray radiation, this property is simply the gray absorption coefficient. For spectral radiation, it is defined as: $κ_{t o t a l} = (\sum_{i \in b a n d s}^{} n_{i}^{2} κ_{i} E_{b, i}) / (\sum_{i \in b a n d s}^{} E_{b, i})$ where $n$ is the index of refraction, $E_{b}$ is the blackbody emissive power and the subscript $i$ denotes the band.

The following primitive field functions are additionally made available when the View Factors Calculator model or the Surface Photon Monte Carlo (SPMC) radiation model is activated.


Radiation Patch Id	An ID number identifying the boundary face the patch belongs to.
Radiation Patch Id on External Side	An ID number identifying the boundary face the patch belongs to.
Voxel partition	The partition ID of the voxel mesh, which is used for view factor ray tracing. The voxel mesh has different domain decomposition from the CFD mesh.

The following primitive field functions are additionally made available only when the View Factors Calculator model is activated.


Filtered Incoming Radiation	The radiation coming into a boundary from a selection of other parts in the simulation.	Parts Selects the parts participating in the view factor calculation. For the external side, you can also use a threshold-derived part, which has its input as parts participation in the view factor simulation, as input. This selection allows you to make a more fine-grained analysis, such as to find the origin point of the radiation, for high temperature faces. The following properties allow you to find the origin of radiation among non-part based inputs: Include Environment When On, includes the diffuse solar flux from the environment in the incoming radiation. Include Direct Solar When On, includes the direct solar flux in the incoming radiation. Include Directional Flux When On, includes the directional flux in the incoming radiation.
Filtered Incoming Radiation on External Side	The radiation coming into the external side of a boundary from a selection of other parts in the simulation.
Filtered Outgoing Radiation	The diffuse radiation going out of a boundary to a selection of other parts in the simulation.	Parts Selects the parts participating in the view factor calculation.
Filtered Outgoing Radiation on External Side	The diffuse radiation going out of the external side of a boundary to a selection of other parts in the simulation.