Muhammad Osama

The long-time dynamics of a quiescent finite-size three-dimensional air filament in a static liquid is studied using three-dimensional numerical simulations. The two ends of the air filament retract under the effect of surface tension and form bulges. A long filament with the aspect ratio Γ = 30 is considered to trigger the end-pinching regime of the filament rupture. The study focuses on the effect of the Ohnesorge number, which relates viscous forces to inertia and surface tension forces. Depending on the value of the Ohnesorge number, two or three successive ruptures of the filament are observed. Wavy structures form at the interface of the air filament after the first rupture and lead to a subsequent breakup in the middle of the filament or in several places depending on the corresponding Ohnesorge number. The size distribution of the bubbles generated is provided and shows an average diameter twice as large as the initial diameter of the air filament. Microbubbles are generated, and their number is shown to increase when the Ohnesorge number decreases.