On the stabilizing effect of a liquid film on a cylindrical core by oscillatory motions

Liquid films on cylindrical bodies like wires or fibres disintegrate if their length exceeds a critical size (Plateau-Rayleigh instability). Stabilization can be achieved by an axial oscillation of the solid core provided that a suitable combination of forcing amplitude and frequency is given. To investigate the stabilizing effect, direct numerical simulations (DNS) of the axisymmetric problem are conducted with a height function based solver. It is found that the mechanism of film stabilization is caused by the interaction between an inertia dominated region (high film thickness) and a viscosity dominated region (low film thickness). Replenishing of the thin film region is thereby supported while depleting is suppressed, finally leading to a stable film flow on an oscillating cylinder. To the end, a systematic variation of the main system parameters, e.g., the Weber number, the ratio between the radius of the inner core and the average film coating thickness, and the oscillation frequency is presented and the influence of the parameters discussed.