Regimes of wettability-dependent and wettability-independent bouncing of a drop on a solid surface

Kumar, Praveen; Dixit, Harish N.

doi:10.1017/jfm.2020.773

Cited by 12 publications

(8 citation statements)

References 53 publications

(244 reference statements)

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“…In a recent report, Zhang et al, also showed interfacial perturbations at the liquid–air interface induced by the top surface collapse, which purportedly triggered a thin film instability when the wavelength of the perturbing capillary waves exceeded a critical value . Similar fluctuations in the liquid–air interface induced by the strong oscillation on the upper surface of the drop was further probed via simulation by Sharma and Dixit . Noting the pronounced perturbations of the drop-air interface during both the spreading and retraction phases, we attribute the contact bouncing mechanism to be strongly tied to the bottom surface undulations during rebound which is aided by the liquid film deformation.…”

Section: Discussionsupporting

confidence: 61%

“…Drop oscillation dynamics in-flight has been shown to be important in recent works where the oscillation decay is a strong function of the We and Re d .For instance, small undulations on the lower surface of a falling drop occurs when Re d ≫ We. 60 The oscillation decay time for an in-flight drop is given by τ decay = ρ(D 0 /2) 2 /(5 μ) ≈248 ms, reported earlier by Lamb. 61 However, the longest flight time scale t f = U 0 /g ≈ 60 ms, given by the largest impact velocity in our experiment, which is at least four times smaller than the oscillation decay time.…”

Section: ■ Discussionmentioning

confidence: 61%

“…We attribute the probabilities of contact to the precontact dynamics such as drop oscillation. Drop oscillation dynamics in-flight has been shown to be important in recent works where the oscillation decay is a strong function of the We and Re d .For instance, small undulations on the lower surface of a falling drop occurs when Re d ≫ We . The oscillation decay time for an in-flight drop is given by τ decay = ρ( D 0 /2) 2 /(5 μ) ≈248 ms, reported earlier by Lamb .…”

Section: Discussionmentioning

confidence: 64%

“…56 Similar fluctuations in the liquid−air interface induced by the strong oscillation on the upper surface of the drop was further probed via simulation by Sharma and Dixit. 60 Noting the pronounced perturbations of the drop-air interface during both the spreading and retraction phases, we attribute the contact bouncing mechanism to be strongly tied to the bottom surface undulations during rebound which is aided by the liquid film deformation.…”

Section: ■ Discussionmentioning

confidence: 87%

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Drop Bouncing Dynamics on Ultrathin Films

Tran

Pack

2021

Langmuir

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presented for the various drop impact regimes for the thin (i.e., O(1 μm))and thick (i.e., O(100 μm)) liquid film thickness limits. The incidence of the contact bouncing phenomenon was also characterized and found to be intimately tied to the late-stage gas film failure where a small volume of liquid is deposited onto the liquid film prior to bouncing. This study sheds new light on the bouncing-merging transitions for drops on ultrathin liquid films and gas entrainment dynamics relevant to applications such as precise drop deposition techniques.

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Section: Discussionsupporting

confidence: 61%

Section: ■ Discussionmentioning

confidence: 61%

Section: Discussionmentioning

confidence: 64%

Section: ■ Discussionmentioning

confidence: 87%

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Drop Bouncing Dynamics on Ultrathin Films

Tran

Pack

2021

Langmuir

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“…One basic question is whether the drop liquid is in direct contact with the solid surface at the moment of determining the contact angle [35]. It was found that droplets bounce off of a surface if the surface happens to be nonwetted by the droplet phase, however, it has also been reported that there exists a fluid cushion which appears also when the surface is wetted by the droplet [36]. This is confirmed by Fig.…”

Section: Introductionmentioning

confidence: 79%

Experimental determination of wetting behavior under non-atmospheric conditions relevant to reservoirs: a practical guide

Samara

Jaeger

2022

SN Appl. Sci.

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The wetting behavior in subsurface reservoirs plays a crucial role in storage, migration and liberation of fluid phases that are especially relevant to the energy sector. Further, the three-phase contact angle is important for implementing safe and successful subsurface storage of hydrogen and carbon dioxide. For reliable statements on the in situ wetting, it is important to be aware of the decisive factors of influence in order to design and perform the respective experiments in an appropriate way. This paper discusses the most important effects that shall be considered when determining contact angles experimentally, like drop size, surface roughness, aging process, dynamic behavior, and the pH, giving some valuable guidance to guarantee significant results. A drop base diameter of no less than 5 mm is found to be appropriate to minimize the impact of gravity on the contact angle under reservoir conditions. It is further confirmed that surface roughness contributes to better water wetting when the contact angles are below 90°. The versatility of contact angle measurements is shown through the dual-drop dual-crystal method that can be applied to estimate the adhesion forces present at the rock-brine interface and that need to be overcome by the flooding liquid to effectively displace hydrocarbons from the pores.

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Drop impact on viscous liquid films

et al. 2023

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When a liquid drop falls on a solid substrate, the air layer between them delays the occurrence of liquid–solid contact. For impacts on smooth substrates, the air film can even prevent wetting, allowing the drop to bounce off with dynamics identical to that observed for impacts on superamphiphobic materials. In this paper, we investigate similar bouncing phenomena, occurring on viscous liquid films, that mimic atomically smooth substrates, with the goal to probe their effective repellency. We elucidate the mechanisms associated with the bouncing to non-bouncing (floating) transition using experiments, simulations, and a minimal model that predicts the main characteristics of drop impact, the contact time and the coefficient of restitution. In the case of highly viscous or very thin films, the impact dynamics is not affected by the presence of the viscous film. Within this substrate-independent limit, bouncing is suppressed once the drop viscosity exceeds a critical value, as on superamphiphobic substrates. For thicker or less viscous films, both the drop and film properties influence the rebound dynamics and conspire to inhibit bouncing above a critical film thickness. This substrate-dependent regime also admits a limit, for low-viscosity drops, in which the film properties alone determine the limits of repellency.

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Regimes of wettability-dependent and wettability-independent bouncing of a drop on a solid surface

Abstract: Abstract

Cited by 12 publications

References 53 publications

Drop Bouncing Dynamics on Ultrathin Films

Drop Bouncing Dynamics on Ultrathin Films

Experimental determination of wetting behavior under non-atmospheric conditions relevant to reservoirs: a practical guide

Drop impact on viscous liquid films

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