We investigate the properties of dissipative full discretizations
for the equations of motion associated with
models of flow and radiative transport inside stars. We derive
dissipative space discretizations and demonstrate that together
with specially adapted total-variation-diminishing (TVD) Runge-Kutta
time discretizations with adaptive step-size control this yields
reliable and efficient integrators for the underlying high-dimensional
nonlinear evolution equations. In particular, TVD SDIRK methods
in conjunction with fixed point iteration are demonstrated to
yield improved accuracy at a performance comparable to explicit
Runge-Kutta schemes. In some physical situations it is more advantageous to
use partitioned IMEX Runge-Kutta schemes, where the solution of
the nonlinear implicit part can be realized by the solution of a
Poisson problem.