Understanding Default Nodes in Radiation Modeling: Absorbing-Scattering Medium, Opaque Surface, and Continuity on Interior Boundary

When simulating radiation in absorbing and scattering media, understanding the role of default nodes is crucial for accurate model setup. This article explains the functions of key nodes that are automatically added to the Model Builder upon selecting the physics interface.

Default Nodes Explained

• Absorbing-Scattering Medium: This node defines the medium through which radiation travels and interacts. It considers both absorption, where radiation energy is absorbed by the medium, and scattering, where radiation changes direction. Properties like the absorption and scattering coefficients are defined here.
• Opaque Surface: This node represents surfaces that are completely opaque to radiation, meaning no radiation can pass through them. It's typically used to define the outer boundaries of the simulation domain or opaque objects within the domain.
• Continuity on Interior Boundary: This node, added when using the 'Discrete Ordinates Method,' ensures radiation continuity across internal boundaries within the domain. This is essential for accurately modeling radiation transport in complex geometries.

Adding Boundary Conditions and Physics Features

To further refine your model, you can add boundary conditions and other physics features. Right-clicking the main node allows you to specify conditions like incident radiation, temperature, or heat fluxes at specific boundaries. Moreover, the Physics toolbar offers additional nodes for implementing various boundary conditions. For instance, you can define a surface as a blackbody emitter or specify a specularly reflecting surface. Additionally, right-clicking the 'Radiation in Absorbing-Scattering Media' node provides access to context-specific physics features through the context menu, allowing for further customization and accuracy in your radiation model.