scholarly journals Submicron drops from flapping bursting bubbles

2022 ◽  
Vol 119 (1) ◽  
pp. e2112924119
Author(s):  
Xinghua Jiang ◽  
Lucas Rotily ◽  
Emmanuel Villermaux ◽  
Xiaofei Wang
Keyword(s):  
Critical Role ◽  
Shear Instability ◽  
Radius Of Curvature ◽  
Air Bubbles ◽  
Capillary Length ◽  
Bubble Bursting ◽  
Air Water Interface ◽  
Water Drops ◽  
Present Understanding ◽  
Outer Environment

Tiny water drops produced from bubble bursting play a critical role in forming clouds, scattering sunlight, and transporting pathogens from water to the air. Bubbles burst by nucleating a hole at their cap foot and may produce jets or film drops. The latter originate from the fragmentation of liquid ligaments formed by the centripetal destabilization of the opening hole rim. They constitute a major fraction of the aerosols produced from bubbles with cap radius of curvature (R) > ∼0.4 × capillary length (a). However, our present understanding of the corresponding mechanisms does not explain the production of most submicron film drops, which represent the main number fraction of sea spray aerosols. In this study, we report observations showing that bursting bubbles with R < ∼0.4a are actually mainly responsible for submicron film drop production, through a mechanism involving the flapping shear instability of the cap with the outer environment. With this proposed pathway, the complex relations between bubble size and number of drops produced per bubble can be better explained, providing a fundamental framework for understanding the production flux of aerosols and the transfer of substances mediated by bubble bursting through the air–water interface and the sensitivity of the process to the nature of the environment.

Bursting bubble aerosols

2011 ◽  
Vol 696 ◽  
pp. 5-44 ◽  
Author(s):  
H. Lhuissier ◽  
E. Villermaux
Keyword(s):  
Film Thickness ◽  
Original Film ◽  
Drop Size ◽  
Radius Of Curvature ◽  
Aerosol Formation ◽  
Capillary Length ◽  
Air Bubble ◽  
Bubble Bursting ◽  
Drainage Rate ◽  
Spray Structure

AbstractWe depict and analyse the complete evolution of an air bubble formed in a water bulk, from the time it emerges at the liquid surface, up to its fragmentation into dispersed drops. To this end, experiments describing the drainage of the bubble cap film, its puncture and the resulting bursting dynamics determining the aerosol formation are conducted on tapwater bubbles. We discover that the mechanism of marginal pinching at the bubble foot and associated convection motions in the bubble cap, known as marginal regeneration, both drive the bubble cap drainage rate, and are responsible for its puncture. The resulting original film thickness $h$ evolution law in time, supplemented with considerations about the nucleation of holes piercing the film together culminate in a determination of the cap film thickness at bursting ${h}_{b} \propto {R}^{2} / \mathscr{L}$, where $R$ is the bubble cap radius of curvature, and $\mathscr{L}$ a length which we determine. Subsequent to a hole nucleation event, the cap bursting dynamics conditions the resulting spray. The latter depends both on the bubble shape prescribed by $R/ a$, where $a$ is the capillary length based on gravity, and on ${h}_{b} $. The mean drop size $\langle d\rangle \ensuremath{\sim} {R}^{3/ 8} \hspace{0.167em} { h}_{b}^{5/ 8} $, the number of drops generated per bubble $N\ensuremath{\sim} \mathop{ (R/ a)}\nolimits ^{2} \mathop{ (R/ {h}_{b} )}\nolimits ^{7/ 8} $ and the drop size distribution $P(d)$ are derived, comparing well with measurements. Combined with known bubble production rates over the ocean, our findings offer an adjustable parameter-free prediction for the aerosol flux and spray structure caused by bubble bursting in this precise context.

Critical role of nanocomposites at air–water interface: From aqueous foams to foam-based lightweight functional materials

2021 ◽  
Vol 416 ◽  
pp. 129121
Author(s):  
Kai Yu ◽  
Bin Li ◽  
Huagui Zhang ◽  
Zhentao Wang ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Critical Role ◽  
Functional Materials ◽  
Water Interface ◽  
Aqueous Foams ◽  
Air Water Interface

The Lobe Structure in Ice Accreted on an Aluminium Conductor in The Presence of a Dc Electric Field

1983 ◽  
Vol 4 ◽  
pp. 228-235 ◽  
Author(s):  
Luan C. Phan ◽  
Jean-Louis Laforte ◽  
Du D. Nguyen
Keyword(s):  
Electric Field ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Air Bubbles ◽  
Experimental Conditions ◽  
Charged Droplets ◽  
Water Drops ◽  
The Difference ◽  
Negative Electric Field ◽  
Corona Wind

Supercooled droplets of 38 μm mean volume diameter are accreted on a smooth aluni mum cylinder of 3.15 cm in diameter in order to study the effect of an electrostatic field upon ice formation on a power-line conductor. The results obtained show that ice grown in the presence of an applied negative field of 15 kV cm−1 exhibits a cusped-lobe structure characterized by surfacial outward knobs, convex rings of fine air bubbles and radial lines of large air bubbles; in the same conditions, a positive electric field of 15 kV cm−1 does not produce such lobe features. On the other hand, accretion tests performed in the absence of an electric field with a 33 μm droplet spectrum show that the well-developed cusped-lobe structure appears in ice at low ambient temperature and air velocity. In the present experimental conditions, the formation of cusped lobes observed in the presence of a negative electric field could be explained by a decrease in the temperature of the deposit due to a reduction of impact velocity of the charged droplets and/or an increase in the local heat-transfer coefficient at the surface of the ice accretion. Corona wind from ice points, always in the opposite direction to the impinging droplets, may also reduce their impact velocities. In addition, corona wind and roughness of the surface may contribute to a better evacuation of the latent heat and thus decrease the deposit temperature. The difference between the effects of a negative DC field and those of a DC positive field of the same strength comes from a stronger ionization intensity and/or a stronger deformation of water drops in the negative electric field.

scholarly journals Steep capillary-gravity waves in oscillatory shear-driven flows

2009 ◽  
Vol 640 ◽  
pp. 131-150 ◽  
Author(s):  
SHREYAS V. JALIKOP ◽  
ANNE JUEL
Keyword(s):  
Surface Tension ◽  
Gravity Waves ◽  
Pitchfork Bifurcation ◽  
Nonlinear Regime ◽  
Radius Of Curvature ◽  
Square Root ◽  
Capillary Length ◽  
Weakly Nonlinear ◽  
Gravitational Forces ◽  
Steep Waves

We study steep capillary-gravity waves that form at the interface between two stably stratified layers of immiscible liquids in a horizontally oscillating vessel. The oscillatory nature of the external forcing prevents the waves from overturning, and thus enables the development of steep waves at large forcing. They arise through a supercritical pitchfork bifurcation, characterized by the square root dependence of the height of the wave on the excess vibrational Froude number (W, square root of the ratio of vibrational to gravitational forces). At a critical valueWc, a transition to a linear variation inWis observed. It is accompanied by sharp qualitative changes in the harmonic content of the wave shape, so that trochoidal waves characterize the weakly nonlinear regime, but ‘finger’-like waves form forW≥Wc. In this strongly nonlinear regime, the wavelength is a function of the product of amplitude and frequency of forcing, whereas forW<Wc, the wavelength exhibits an explicit dependence on the frequency of forcing that is due to the effect of viscosity. Most significantly, the radius of curvature of the wave crests decreases monotonically withWto reach the capillary length forW=Wc, i.e. the lengthscale for which surface tension forces balance gravitational forces. ForW<Wc, gravitational restoring forces dominate, but forW≥Wc, the wave development is increasingly defined by localized surface tension effects.

Facile Fabrication of Super-Hydrophobic Surface on Aluminum and its Effects in Accelerating Underwater Bubble Bursting

2014 ◽  
Vol 789 ◽  
pp. 154-156
Author(s):  
Chun Mao Kang ◽  
Jin Yan Ji ◽  
Jun Li Zhao ◽  
Hong Peng Zhong ◽  
Jiao He ◽  
...  
Keyword(s):  
Hydrophobic Surface ◽  
Fiber Spinning ◽  
Aluminum Surface ◽  
Air Bubbles ◽  
Practical Application ◽  
Energy Materials ◽  
Bubble Bursting ◽  
One Step ◽  
Facile Fabrication ◽  
Fundamental Research

Facile fabrication of bio-mimic super-hydrophobic surfaces has attracted attentions in both fundamental research and practical application. In this article, we developed a simple one step etching method to fabricate a super-hydrophobic surface on aluminum surface. The contact angel of water reaches 155.9° without coating any low energy materials. Surface morphology clearly demonstrates a combination of micro/nanohierarchical structures. Moreover, such surface remarkably shortens the bursting time of air bubbles under water. For a middle size bubble about 1mm, the bursting time at super-hydrophobic surface shortens to about 20%, comparing to freely bursting. This intriguing effect may contribute to future expand applications of super-hydrophobic surface in industrial field, such as fiber spinning.

A Study on Langmuir Monolayers of Methacrylate Homo- and Copolymers Derivatized with Disperse Red Dyes

1997 ◽  
Vol 488 ◽  
Author(s):  
Anantharaman Dhanabalan ◽  
Débora Balogh ◽  
Carlos José Leopoldo Constantino ◽  
Antonio Riul ◽  
Osvaldo N. Oliveira ◽  
...  
Keyword(s):  
Surface Pressure ◽  
Critical Role ◽  
Langmuir Monolayers ◽  
Water Interface ◽  
Chlorine Substitution ◽  
Air Water Interface ◽  
Mole Percentage ◽  
Disperse Red 1 ◽  
Red Dye

AbstractWe report on the organization of different disperse red dye derivatized methacrylate homo- and copolymers as Langmuir monolayers at the air-water interface. The monolayers were investigated using surface pressure and surface potential isotherms. Methacrylic homopolymers containing disperse red-1 (HPDR1) and disperse red-13 (HPDR13) and methacrylic copolymers with different mole percentages of the dye and hydroxyethyl spacer groups were synthesized and characterized. A comparison of the monolayer characteristics of HPDR1 and HPDR13 revealed the influence of the chlorine substitution in the aromatic ring of the dye. Studies with copolymers indicated a clear transition in the monolayer behavior with the change of mole percentage of the dye incorporated in the polymer. While copolymers with low dye content (up to about 5 mole%) presented an expanded monolayer, the copolymers containing higher dye content (12% and above) formed a condensed monolayer similar to that of the homopolymer. These results indicated the critical role of the dye component in the polymer chain in forming the monolayer at the air-water interface.

scholarly journals Plunging jets from orifices of different geometry

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Giorgio Moscato ◽  
Giovanni Paolo Romano
Keyword(s):  
Reynolds Number ◽  
Reynolds Numbers ◽  
Air Bubbles ◽  
Natural Processes ◽  
Water Jets ◽  
Starting Point ◽  
Air Water Interface ◽  
Plunging Jets ◽  
Small Reynolds Numbers ◽  
Jet Characteristics

Plunging jets are used in many industrial and civil applications, as for example in sewage and water treatment plants, in order to enhance aeration and mass transfer of volatile gases. They are also observed in natural processes as rivers self-purification, waterfalls and weirs. Many investigations dealt with the plunging jets in different configurations, but the dependence on Reynolds number and jet geometry were still not sufficiently addressed. For example, Mishra et al. (2020) studied an oblique submerged water impinging jet at different nozzle-to-plate distances and impingement angles, but only at a rather small Reynolds numbers (2600). On the other hand, different jet geometries have been extensively considered, but not for the plunging jet configuration (Mi, 2000; Hashiehbaf &Romano, 2013). In this work, plunging water jets issuing in air from orifices of different shape are considered. The aim of the work is to detail and compare jet behaviors in terms of velocity fields generated after impacting the air-water interface, as a function of Reynolds number and orifice geometry. However, air bubbles entrainment is mainly avoided in order to study the jet characteristics in a simpler case and use it as a reference starting point for future works.

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