  This work investigates the capillary rise dynamics of highly wetting liquids
in a divergent U-tube in the microgravity conditions provided by 78th European
Space Agency (ESA) parabolic flight. This configuration produces a
capillary-driven channel flow. We use image recording in backlight illumination
to characterize the interface dynamics and dynamic contact angle of HFE7200 and
Di-Propylene Glycol (DPG). For the case of HF7200, we complement the interface
measurements with Particle Tracking Velocimetry (PTV) to characterize the
velocity fields underneath the moving meniscus. In the experiments with DPG,
the liquid column reaches different heights within various experiments, and the
measurements show a sharp reduction of the meniscus curvature when the contact
line moves from a pre-wet to a dry substrate. In experiments with HFE7200, the
interface always moves on a pre-wet surface. Yet a curvature reduction is
observed due to the inertial forces on the underlying accelerating flow. The
PTV measurements show that the distance from the interface within which the
velocity profile adapts to the meniscus velocity shortens as the interface
acceleration increases.
