  The dynamics of individual liquid plugs pushed at constant pressure head
inside prewetted cylindrical capillary tubes is investigated experimentally and
theoretically. It is shown that, depending on the thickness of the prewetting
film and the magnitude of the pressure head, the plugs can either experience a
continuous acceleration leading to a dramatic decrease of their size and
eventually their rupture or conversely, a progressive deceleration associated
with their growth and an exacerbation of the airway obstruction. These
behaviors are quantitatively reproduced with a simple nonlinear model [Baudoin
et al., Proc. Nat. Ac. Sci. USA, 2013, 110, 859] adapted here for cylindrical
channels. Furthermore, an analytical criterion for the transition between these
two regimes is derived and successfully compared with extensive experimental
data. The potential implications of this work for pulmonary obstructive
diseases are discussed.
