  We study the deformation and dewetting of liquid films under impinging gas
jets using experimental, analytical and numerical techniques. We first derive a
reduced-order model (a thin-film equation) based on the long-wave assumption
and on appropriate decoupling of the gas problem from that for the liquid. The
model not only provides insight into relevant flow regimes, but is also used in
conjunction with experimental data to guide more computationally prohibitive
direct numerical simulations (DNS) of the full governing equations. A unique
feature of our modelling solution is the use of an efficient iterative
procedure in order to update the interfacial deformation based on stresses
originating from computational data. We show that both gas normal and
tangential stresses are equally important for achieving accurate predictions.
The interplay between these techniques allows us to study previously unreported
flow features. These include finite-size effects of the host geometry, with
consequences for flow and vortex formation inside the liquid, as well as the
specific individual contributions from the non-trivial gas flow components on
interfacial deformation. Dewetting phenomena are found to depend on either a
dominant gas flow or contact line motion, with the observed behaviour
(including healing effects) being explained using a bifurcation diagram of
steady-state solutions in the absence of the gas flow.
