Cloud angular momentum and effective viscosity in global SPH simulations
  with feedback
  We examine simulations of isolated galaxies to analyse the effects of
localised feedback on the formation and evolution of molecular clouds. Feedback
contributes to turbulence and the destruction of clouds, leading to a
population of clouds that is younger, less massive, and with more retrograde
rotation. We investigate the evolution of clouds as they interact with each
other and the diffuse ISM, and determine that the role of cloud interactions
differs strongly with the presence of feedback: in models without feedback,
scattering events dramatically increase the retrograde fraction, but in models
with feedback, mergers between clouds may slightly increase the prograde
fraction. We also produce an estimate of the viscous time-scale due to
cloud-cloud collisions, which increases with increasing strength of feedback
(~20 Gyr vs ~10 Gyr), but is still much smaller than previous estimates (~1000
Gyr); although collisions become more frequent with feedback, less energy is
lost in each collision than in the models without feedback.
