  We investigate the behaviour of accelerating contact lines in an unsteady
quasi-capillary channel flow. The configuration consists of a liquid column
that moves along a vertical 2D channel, open to the atmosphere and driven by a
controlled pressure head. Both advancing and receding contact lines were
analyzed to test the validity of classic models for dynamic wetting and to
study the flow field near the interface. The operating conditions are
characterized by a large acceleration, thus dominated by inertia. The shape of
the moving meniscus was retrieved using Laser-Induced Fluorescence (LIF)-based
image processing while the flow field near was analyzed via Time-Resolved
Particle Image Velocimetry (TR-PIV). The TR-PIV measurements were enhanced in
the post-processing, using a combination of Proper Orthogonal Decomposition
(POD) and Radial Basis Functions (RBF) to achieve super-resolution of the
velocity field. Large counter-rotating vortices were observed, and their
evolution was monitored in terms of the maximum intensity of the Q-field. The
results show that classic contact angle laws based on interface velocity cannot
describe the evolution of the contact angle at a macroscopic scale. Moreover,
the impact of the interface dynamics on the flow field is considerable and
extends several capillary lengths below the interface.
