Jet drops from bursting bubbles: How gravity and viscosity couple to inhibit droplet production

Abstract

When a bubble ruptures at a liquid surface the collapsing cavity produces a central jet that frequently breaks up into a series of droplets. Current experiment and theory predict that the production of jet drops will be limited by either viscous or gravitational effects. However, while there are a number of studies focusing on these two limiting cases, less is understood about the production of jet drops when both gravitational and viscous effects are significant. Here, we uncover the existence of an intermediate region where both gravitational and viscous effects play a critical role in jet-drop formation. We propose that the role of gravity is most important before rupture, and carry out simulations that demonstrate the importance of the equilibrium bubble shape in the production of jet drops.

Scaling laws of top jet drop size and speed from bubble bursting including gravity and inviscid limit

“…In other words, one should have t D > t o , which immediately implies that the Ohnesorge number Oh = µ (ρσRo) 1/2 should be below a critical one (here, Oh 1 ) to have a sufficiently energetic jetting for droplet ejection. That critical number Oh 1 was experimentally calculated by Walls et al [14], including the influence of the gravity using the Bond number Bo = ρgR 2 o /σ. In the limit of very small Bo numbers, they obtained Oh 1 0.037, which was confirmed in [15].…”

Aerosolization of Crude Oil‐Dispersant Slicks Due to Bubble Bursting

“…Another factor, presumably most important, that has been shown to suppress the jetting process is the viscous damping of the capillary waves on the surface of the cavity (Lee et al, ; Walls et al, ). The critical bubble diameter ( d b c ) below which the jetting is suppressed has been expressed as a critical Ohnesorge number, Oh c =μ/(σρd b c /2) 0.5 , which falls in the 0.037–0.052 range.…”

Bursting dynamics of viscous film without circular symmetry: The effect of confinement

“…[7,8] Dewetting, i.e., bursting of a film deposited on a substrate, is another topic that has attracted much attention [9][10][11]. More practically, bursting is an important tool for generation of droplets [3,[12][13][14][15][16][17] or emulsions [18] with controlled sizes because at a later stage a liquid rim formed at the bursting tip destabilizes to break into droplets.The size of droplets is a crucial factor in various fields such as environmental science [19] or disease transfer [20] because contamination results often via droplets. Bubble bursting is also important to bioreactor efficiency, because bursting is one of the causes of cell damage [21][22][23].Taking a closer look at the bursting of liquid film suspended in air, which is the base of all the above mentioned issues, only two scaling regimes have been established, one is called inertial regime and the other viscous (or viscoelastic) regime.…”

“…[7,8] Dewetting, i.e., bursting of a film deposited on a substrate, is another topic that has attracted much attention [9][10][11]. More practically, bursting is an important tool for generation of droplets [3,[12][13][14][15][16][17] or emulsions [18] with controlled sizes because at a later stage a liquid rim formed at the bursting tip destabilizes to break into droplets.…”