PLUTO Test Problems
4.4-patch2
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Radiation pulse test in optically thin and thick media. More...
Sets the initial condition for a radiation pulse in an optically thin or thick medium. Radiation energy is initially set as , with
where r is the spherical radius. Uniform values of the gas density and pressure are set in such a way that the temperature satisfies . We also set
and
in the whole domain. In every setup an absorption opacity
is chosen.
The following setups are implemented:
Configuration #05 corresponds to a Cartesian 1D setup in which , so that the domain is largely optically thick (
across the domain). In that case, the radiation flux becomes
, and the radiation energy evolves according to the following diffusion equation:
By setting RADIATION_DIFF_LIMITING
to NO
, it can be seen that this option considerably reduces the artificial numerical diffusion that can in opaque systems if signal speeds are overestimated. It can also be seen that setting RADIATION_IMEX_SSP2
to YES
produces a miscalculation of the radiation flux, as detailed in Melon Fuksman and Mignone (2019).
References