  Employing a long-wave mesoscopic hydrodynamic model for the film height
evolution we study ensembles of pinned and sliding drops of a volatile liquid
that continuously condense onto a chemically heterogeneous inclined substrate.
Our analysis combines, on the one hand, path continuation techniques to
determine bifurcation diagrams for the depinning of single drops of nonvolatile
liquid on single hydrophilic spots on a partially wettable substrate and, on
the other hand, time simulations of growth and depinning of individual
condensing drops as well as of the long-time behaviour of large ensembles of
such drops. Pinned drops grow on the hydrophilic spots, depin and slide along
the substrate while merging with other pinned drops and smaller drops that
slide more slowly, and possibly undergo a pearling instability. As a result,
the collective behaviour converges to a stationary state where condensation and
outflow balance. The main features of the emerging drop size distribution can
then be related to single-drop bifurcation diagrams.
