  We present numerical results on two- (2D) and three-dimensional (3D)
hydrodynamic core-collapse simulations of an 11.2$M_\odot$ star. By changing
numerical resolutions and seed perturbations systematically, we study how the
postbounce dynamics is different in 2D and 3D. The calculations were performed
with an energy-dependent treatment of the neutrino transport based on the
isotropic diffusion source approximation scheme, which we have updated to
achieve a very high computational efficiency. All the computed models in this
work including nine 3D models and fifteen 2D models exhibit the revival of the
stalled bounce shock, leading to the possibility of explosion. All of them are
driven by the neutrino-heating mechanism, which is fostered by neutrino-driven
convection and the standing-accretion-shock instability (SASI). Reflecting the
stochastic nature of multi-dimensional (multi-D) neutrino-driven explosions,
the blast morphology changes from models to models. However, we find that the
final fate of the multi-D models whether an explosion is obtained or not, is
little affected by the explosion stochasticity. In agreement with some previous
studies, higher numerical resolutions lead to slower onset of the shock revival
in both 3D and 2D. Based on the self-consistent supernova models leading to the
possibility of explosions, our results systematically show that the revived
shock expands more energetically in 2D than in 3D.
