  Wet granular materials in a quasi-static steady state shear flow have been
studied with discrete particle simulations. Macroscopic quantities, consistent
with the conservation laws of continuum theory, are obtained by time averaging
and spatial coarse-graining. Initial studies involve understanding the effect
of liquid content and liquid properties like the surface tension on the
macroscopic quantities. Two parameters of the liquid bridge contact model have
been studied as the constitutive parameters that define the structure of this
model (i) the rupture distance of the liquid bridge model, which is
proportional to the liquid content, and (ii) the maximum adhesive force, as
controlled by the surface tension of the liquid. Subsequently a correlation is
developed between these micro parameters and the steady state cohesion in the
limit of zero confining pressure. Furthermore, as second result, the
macroscopic torque measured at the walls, which is an experimentally accessible
parameter, is predicted from our simulation results as a dependence on the
micro-parameters. Finally, the steady state cohesion of a realistic non-linear
liquid bridge contact model scales well with the steady state cohesion for a
simpler linearized irreversible contact model with the same maximum adhesive
force and equal energy dissipated per contact.
