Holes-driven rupture: unveiling the dynamics of liquid sheet atomization

The atomization of liquid sheets by airflow is a fundamental process with significant implications for airborne disease transmission and agricultural pesticide application. As airflow thins these sheets, holes can nucleate in regions of minimal thickness, leading to sheet breakup following the Taylor–Culick-type mechanism. Here, we show that impurities within liquid sheets, such as bubbles or oil droplets, can trigger hole nucleation at thicknesses much greater than molecular scales, challenging previous assumptions about van der Waals forces driving this process. Through direct numerical simulations, we elucidate the mechanisms by which these impurities prompt hole formation during sheet drainage. We characterize the process using the Ohnesorge number Oh (dimensionless viscosity) and the Bond number Bo (dimensionless free-fall acceleration due to inflation of liquid sheets) and examine their influence on the dynamics of impurity-induced hole nucleation. Intuitively, higher Bo results in a prominent sheet breakup. However, counterintuitively, decreasing Oh at fixed Bo stabilizes the sheet. This work provides new insights into the fragmentation of liquid films in various natural and industrial contexts, from respiratory droplet production to spray technologies.