The aerobreakup of bubbles in continuous airflow

Abstract

Floating soap bubbles usually break up owing to gravitational drainage, surface evaporation, environmental disturbances, and collisions with objects. If a gust of wind blows into a bubble, does the bubble break, and, if so, how does it do so? This study reports experiments that use a high-speed camera to examine the dynamic behaviors of a suspended bubble that is suddenly exposed to continuous airflow. Specifically, the behaviors and mechanisms of the aerobreakup of bubbles are explored. The suspended bubble undergoes shedding and deformation under aerodynamic force and flows with airflow. As the Weber number (We) increases, the parameter of Taylor deformation (DT) first increases and then decreases. At a higher Reynolds number, K–H waves appear on the surface of the film owing to the strong shear of airflow on the liquid film. Most such bubbles break due to the shear of the wake vortices on the leeward surface or surface waves on the windward surface, both of which are shearing. The aerobreakup of the bubbles becomes more severe with an increase in We, and they successively exhibit modes of wind-flowing, leeward breakup, windward breakup, and multihole breakup.