Numerical evolution of the interior geometry of charged black holes

Previously, we developed a late time approximation scheme to study the interior geometry of black holes. In the present paper we test this scheme with numerical relativity simulations. In particular, we present numerical relativity simulations of the interior geometry of charged spherically symmetric two-sided black holes with a spacelike singularity at $r = 0$. Our numerics are in excellent agreement with the late time approximation. We also demonstrate that the geometry near $r = 0$ is a scalarized Kasner geometry and compute the associated Kasner exponents.