Constraining viscous dark energy models with the latest cosmological
  data
  Based on the assumption that the dark energy possessing bulk viscosity is
homogenously and isotropically permeated in the universe, we propose three new
viscous dark energy (VDE) models to characterize the accelerating universe. By
constraining these three models with the latest cosmological observations, we
find that they just deviate very slightly from the standard cosmological model
and can alleviate effectively the current $H_0$ tension between the local
observation by the Hubble Space Telescope and the global measurement by the
Planck Satellite. Interestingly, we conclude that a spatially flat universe in
our VDE model with cosmic curvature is still supported by current data, and the
scale invariant primordial power spectrum is strongly excluded at least at the
$5.5\sigma$ confidence level in three VDE models as the Planck result. We also
give the $95\%$ upper limits of the typical bulk viscosity parameter $\eta$ in
three VDE scenarios.
