Dynamics of fluid films flowing down a fibre influenced by nozzle geometry

Viscous thin liquid films flowing down vertical strings can exhibit interesting dynamics via the formation of droplets driven by a Rayleigh mechanism with the presence of gravity. Motivated by experimental results on the effects of nozzle geometry on the dynamics of these viscous droplets by Sadeghpour et al. (2017), we further study a thin film model for the gravity-driven flow in the Rayleigh-Plateau Regime. The governing equation is a fourth-order nonlinear parabolic PDE for the film thickness. Time-dependent computations of the spatial evolution of the film reveal a strong influence of inlet boundary conditions that characterize different nozzle geometry. Numerical solutions of traveling wave solutions also yield information on the profile and propagation velocity of fluid beads, which agrees with available experimental data.