"In Radiation, the hotter body loses heat, and the colder body receives heat by means of a process occurring in some intervening medium which does not itself become thereby hot." - James Clerk Maxwell ^1
In general, Heat Transfer is a process where thermal energy is transferred due to a temperature difference.
The three modes of heat transfer are: Conduction, Convection, and Radiation.
Radiation from a simulation perspective requires a reference temperature (sink temperature) and the emissivity \epsilon.
The radiation heat flux is then calculated with the temperature \tau at the boundary and the Stefan Bolzman constant \sigma:
To learn more about **Radiation** please have a look into our SimWiki.
For more interesting and related articles as well as answers to questions, go to our **SimScale SimWiki**.
^1 : “Theory of heat” by J. Clerk Maxwell - 1871