A fate-alternating transitional regime in contracting liquid filaments

The fate of a contracting liquid filament depends on the Ohnesorge number (Oh), the initial aspect ratio (Γ) and surface perturbation. Generally, it is believed that there exists a critical aspect ratio Γ_c such that longer filaments break up (through Rayleigh-Plateau instability or end-pinching) and shorter ones recoil into a single drop.

Through computational and experimental studies, we report a transitional regime for filaments with a broad range of intermediate aspect ratios. In this regime multiple Γ_c thresholds exist: a novel breakup mode alternates with no-breakup.

We develop a simple model considering the superposition of capillary waves travelling on the free surface from both ends of the filament. The model can predict and explain all fates and breakup mechanisms of the new phase diagram Oh-Γ.