  In this paper, we present a new model to simulate the formation, evolution,
and break up of a thin film of fluid flowing over a curved surface. Referred to
as the discrete droplet method (DDM), the model captures the evolution of thin
fluid films by tracking individual moving fluid droplets. In contrast to
existing thin film models that solve a PDE to determine the film height, here,
we compute the film height by numerical integration based on the aggregation of
droplets. The novelty of this approach in using droplets makes it suitable for
simulating the formation of fluid films, and modelling thin film flows on
partially wetted surfaces. The DDM is a Lagrangian approach, with a force
balance on each droplet governing the motion, and derivatives approximated
using a smoothed particle hydrodynamics (SPH) like approach. The proposed model
is thoroughly validated by comparing results against analytical solutions,
against the results of the shallow-water equations for thin film flow, and also
against results from a full 3D resolved Navier Stokes model. We also present
the use of the DDM on an industrial test case. The results highlight the
effectiveness of the model for simulations of flows with thin films.

Fluid Dynamics