  We perform a joint numerical and experimental study to sistematically
characterize the motion of drops sliding over a periodic array of alternating
hydrophobic and hydrophilic stripes with large wettability contrast, and
typical width of hundreds of $\mu \textrm{m}$. The fraction of the hydrophobic
stripes has been varied from about 20% to 80%. The effects of the heterogeneous
patterning can be described by a renormalized value of the critical Bond
number, i.e. the critical dimensionless force needed to depin the drop before
it starts to move. Close to the critical Bond number we observe a jerkily
motion characterized by an evident stick-slip dynamics. As a result,
dissipation is strongly localized in time, and the mean velocity of the drops
can easily decrease by an order of magnitude compared to the sliding on
homogeneous surface. Lattice Boltzmann (LB) numerical simulations are crucial
for disclosing to what extent the sliding dynamics can be deduced from the
computed balance of capillary, viscous and body forces at varying the Bond
number, the surface composition and the liquid viscosity. Away from the
critical Bond number, we characterize both experimentally and numerically the
dissipation inside the droplet by studying the relation between the average
velocity and the applied volume forces.
