Air sheet contraction

Jian, Zhen; Deng, Peng; Thoraval, Marie-Jean

doi:10.1017/jfm.2020.385

Cited by 11 publications

(5 citation statements)

References 51 publications

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“…Second, our simulations impose axisymmetry, which prevents the air film from rupturing in the azimuthal direction, or from its edge (Jian, Deng & Thoraval 2020 b ). The compressibility effects can be prominent, as the Mach number of the maximum experimental jet speed is , where is the speed of sound, which is independent of ambient pressure.…”

Section: Discussionmentioning

confidence: 99%

Conical focusing: mechanism for singular jetting from collapsing drop-impact craters

2023

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Fast microjets can emerge out of liquid pools from the rebounding of drop-impact craters, or when a bubble bursts at its surface. The fastest jets are the narrowest and are a source of aerosols both from the ocean and from a glass of champagne, of importance to climate and the olfactory senses. The most singular jets, which we observe experimentally at a maximum velocity of $137\pm 4\ {\rm m}\ {\rm s}^{-1}$ and a diameter of $12\ \mathrm {\mu }{\rm m}$ , under reduced ambient pressure, are produced when a small dimple forms at the crater bottom and rebounds without pinching off a small bubble. The radial collapse and rebounding of this dimple is purely inertial, but highly sensitive to initial conditions. High-resolution numerical simulations reveal a new focusing mechanism, which drives the fastest jet within a converging conical channel, where an entrained air sheet provides effective slip at the outer boundary of the conically converging flow into the jet. This configuration bypasses any viscous cutoff of the jetting speed and explains the extreme sensitivity to initial conditions observed in detailed experiments of the phenomenon.

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Section: Discussionmentioning

confidence: 99%

Conical focusing: mechanism for singular jetting from collapsing drop-impact craters

2023

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“…Note that, for very low , as the rim grows with time, the inertial drag on the moving rim due to the surrounding medium overcomes the driving capillary forces, resulting in a decrease of the tip velocity (see insets of figure 6 a and Jian et al. (2020 b )). However, we can still calculate a velocity scale (and hence ) associated with the Taylor–Culick-like retraction immediately after the initial transients (as marked by the black dashed lines in the insets of figure 6 a for the lowest ).…”

Section: Taylor–culick Retractions: Numericsmentioning

confidence: 95%

“…Moreover, for the cases where there is a density contrast between the film and the surroundings, the top–bottom symmetry can break down even for the two-phase configuration due to a flapping instability at very low , as discussed by Lhuissier & Villermaux (2009) and Jian et al. (2020 b ). Furthermore, as increases, the bulbous rim disappears, leading to slender, elongated retracting films.…”

Section: Taylor–culick Retractions: Numericsmentioning

confidence: 95%

“…A question naturally arises: What happens when the outer medium also interacts with the retracting film? In particular, how do the viscosity and the inertia of the outer medium influence the rupture dynamics (Mysels & Vijayendran 1973; Joanny & de Gennes 1987; Reyssat & Quéré 2006; Jian, Deng & Thoraval 2020 b )? A representative schematic for such a scenario is shown in figure 1( b ), where a water film is retracting in a viscous oil ambient.…”

Section: Introductionmentioning

confidence: 99%

“…Common realizations of this configuration include relaxation of filaments and droplets in a viscous medium (Stone & Leal 1989), or that of air-films during drop impact (Jian et al. 2020 a , b ). Additionally, in this context, Anthony, Harris & Basaran (2020) showed that the so-called ‘inertially limited viscous regime’ in the early-times of drop coalescence (Paulsen et al.…”

Section: Introductionmentioning

confidence: 99%

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Taylor–Culick retractions and the influence of the surroundings

et al. 2022

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When a freely suspended liquid film ruptures, it retracts spontaneously under the action of surface tension. If the film is surrounded by air, the retraction velocity is known to approach the constant Taylor–Culick velocity. However, when surrounded by an external viscous medium, the dissipation within that medium dictates the magnitude of the retraction velocity. In the present work, we study the retraction of a liquid (water) film in a viscous oil ambient (two-phase Taylor–Culick retractions), and that sandwiched between air and a viscous oil (three-phase Taylor–Culick retractions). In the latter case, the experimentally measured retraction velocity is observed to have a weaker dependence on the viscosity of the oil phase as compared with the configuration where the water film is surrounded completely by oil. Numerical simulations indicate that this weaker dependence arises from the localization of viscous dissipation near the three-phase contact line. The speed of retraction only depends on the viscosity of the surrounding medium and not on that of the film. From the experiments and the numerical simulations, we reveal unprecedented regimes for the scaling of the Weber number ${We}_{f}$ of the film (based on its retraction velocity) or the capillary number ${Ca}_{s}$ of the surroundings versus the Ohnesorge number ${Oh}_{s}$ of the surroundings in the regime of large viscosity of the surroundings ( ${Oh}_{s} \gg 1$ ), namely ${We}_{f} \sim {Oh}_{s}^{-2}$ and ${Ca}_{s} \sim {Oh}_{s}^{0}$ for the two-phase Taylor–Culick configuration, and ${We}_{f} \sim {Oh}_{s}^{-1}$ and ${Ca}_{s} \sim {Oh}_{s}^{1/2}$ for the three-phase Taylor–Culick configuration.

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Numerical prediction of breakup mode of contracting gas filament in liquid

Cheng

Zhang

et al. 2021

Numerical Methods in Fluids

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The breaking up of gas filament in liquid is important in many industrial and scientific applications. In this study, a transient axisymmetric model with the level set method is built up to examine the dynamics of a contracting gas filament, and to determine the effects of the aspect ratio, Ohnesorge (Oh) number, and viscosity ratio on its breakup mode. The filament undergoes no break, middle break, or end-pinching modes with increasing aspect ratio at either a low or a high Oh number, and one critical initial aspect ratio is observed for each Oh number.The fate of the filament is determined by the interaction of capillary waves on its surface, and can be predicted accurately by using the one-dimensional wave superposition method. The decreasing viscosity ratio of liquid over gas reduces the critical initial aspect ratio for the fate transition between the no break and breakup modes, and this effect is reduced at a low viscosity ratio. These findings may be helpful in fabricating gas bubbles and their breakup suppression.

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Air sheet contraction

Cited by 11 publications

References 51 publications

Conical focusing: mechanism for singular jetting from collapsing drop-impact craters

Conical focusing: mechanism for singular jetting from collapsing drop-impact craters

Taylor–Culick retractions and the influence of the surroundings

Numerical prediction of breakup mode of contracting gas filament in liquid

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