  The wetting behaviour of surfaces is important for various applications like
super-hydrophobic surfaces, enhanced oil recovery, mining of metal ores and
anti-icing surfaces etc. For rough surfaces, which are the rule rather than the
exception, designing textured surfaces that have wetting properties tailored to
suit these applications generally involves either bio-mimicry or trial and
error. Existing wetting theories such as the well-known Wenzel (1936) and
Cassie & Baxter (1944) models do not predict wetting regimes and importantly,
only give a single equilibrium angle rather than a range of stable contact
angles (hysteresis) as observed in reality. In this paper, we use a
roughness-scale mechanical energy balance (derived in part I) combined with
simulations of micro-scale interface dynamics based on open-source software
(Surface Evolver (Brakke 1992)) to calculate the energy dissipation during the
motion of an interface over a chemically homogeneous rough surface. This
dissipation is used to predict contact angle hysteresis (CAH) from knowledge of
just the surface roughness topography and equilibrium contact angle. We
simulate interface dynamics over a surface decorated with a periodic array of
round-edge square pillars and show that the energy dissipated varies
approximately as ${\phi}ln{\phi}$ with the area fraction (${\phi}$), and
becomes zero as ${\phi} \to 0$. The CAH predicted by our method is in good
agreement with the experimental results of Forsberg et al. (2010), especially
at low area fractions. We also compute CAH for an interface moving at
45${\deg}$ to the surface periodicity direction, showing that the experimental
measurements are bracketed by the 0${\deg}$ and 45${\deg}$ advance direction
results.
