  Experimental investigations of the exit dynamics of a horizontal cylindrical
object were performed in water and silicone oil (50 cSt). The fully immersed
cylinder was initially at rest in a still fluid tank before being pushed (or
pulled according to the measurement procedure) upwards at a constant velocity.
Firstly, we demonstrate that these conditions are better satisfied for a large
aspect ratio cylinder equipped with vertical side plates. Secondly, the
influence of the initial depth on the liquid entrained and the wake generated
by the cylinder is discussed. The deformation of the bath is found to be
independent of the starting depth when the starting depth is larger than 6
times the cylinder diameter. In the present case, this criterion reflects also
the finite acceleration of the cylinder to reach the determined constant exit
velocity. Measurements in a range of exit speeds between 0.1 and 1 m/s indicate
that the thickness of the liquid above the cylinder, when the cylinder starts
crossing the interface, increases with the speed according to a logarithmic law
of the Froude number. During the subsequent drainage, the evolution of the
coated liquid thickness is found to first decrease exponentially with time just
after the crossing of the interface. At later times, a change of regime occurs
and the drainage follows the inverse of the square root of time irrespective of
the crossing speed. Finally, the force necessary to maintain a constant exit
speed during the motion of the cylinder inside and outside the bath is
analyzed. This global measurement of the entrained liquid confirms the square
root scaling of the thinning with time during the drainage process.
