  We present a theoretical study related to a recent experiment on the
coalescence of sessile drops. The study deals with the kinetics of relaxation
towards equilibrium, under the action of surface tension, of a spheroidal drop
on a flat surface. For such a nonspherical drop under partial wetting
conditions, the dynamic contact angle varies along the contact line. We propose
a new nonlocal approach to the wetting dynamics, where the contact line
velocity depends on the geometry of the whole drop. We compare our results to
those of the conventional approach in which the contact line velocity depends
only on the local value of the dynamic contact angle. The influence on drop
dynamics of the pinning of the contact line by surface defects is also
discussed.
