  During the core collapse of massive stars that do not undergo a canonical
energetic explosion, some of the hydrogen envelope of a red supergiant (RSG)
progenitor may infall onto the newborn black hole (BH). Within the Athena++
framework, we perform three-dimensional, hydrodynamical simulations of
idealized models of supergiant convection and collapse in order to assess
whether the infall of the convective envelope can give rise to
rotationally-supported material, even if the star has zero angular momentum
overall. Our dimensionless, polytropic models are applicable to the
optically-thick hydrogen envelope of non-rotating RSGs and cover a factor of 20
in stellar radius. At all radii, the specific angular momentum due to random
convective flows implies associated circularization radii of 10 - 1500 times
the innermost stable circular orbit of the BH. During collapse, the angular
momentum vector of the convective flows is approximately conserved and is
slowly varying on the timescale relevant to forming disks at small radii. Our
results indicate that otherwise failed explosions of RSGs lead to the formation
of rotationally-supported flows that are capable of driving outflows to large
radii and powering observable transients. When the BH is able to accrete most
of the hydrogen envelope, the final BH spin parameter is $\sim$ 0.5, even
though the star is non-rotating. For fractional accretion of the envelope, the
spin parameter is generally lower and never exceeds 0.8. We discuss the
implications of our results for transients produced by RSG collapse to a black
hole.

High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics