  The explosion of massive stars in core-collapse supernovae may be aided by
the convective instabilities that develop in their innermost nuclear burning
shells. The resulting fluctuations support the explosion by generating
additional turbulence behind the supernova shock. It was suggested that the
buoyant density perturbations arising from the interaction of the pre-collapse
asymmetries with the shock may be the primary contributor to the enhancement of
the neutrino-driven turbulent convection in the post-shock region. Employing
three-dimensional numerical simulations of a toy model, we investigate the
impact of such density perturbations on the post-shock turbulence. We consider
a wide range of perturbation parameters. The spatial scale and the amplitude of
the perturbations are found to be of comparable importance. The turbulence is
particularly enhanced when the perturbation frequency is close to that of the
convective turnovers in the gain region. Our analysis confirms that the buoyant
density perturbations is indeed the main source of the additional turbulence in
the gain region, validating the previous order-of-magnitude estimates.
