Spherically symmetric cosmological spacetimes with dust and radiation -
  numerical implementation
  We present new numerical cosmological solutions of the Einstein Field
Equations. The spacetime is spherically symmetric with a source of dust and
radiation approximated as a perfect fluid. The dust and radiation are
necessarily non-comoving due to the inhomogeneity of the spacetime. Such a
model can be used to investigate non-linear general relativistic effects
present during decoupling or big-bang nucleosynthesis, as well as for
investigating void models of dark energy with isocurvature degrees of freedom.
We describe the full evolution of the spacetime as well as the redshift and
luminosity distance for a central observer. After demonstrating accuracy of the
code, we consider a few example models, and demonstrate the sensitivity of the
late time model to the degree of inhomogeneity of the initial radiation
contrast.
