Dynamics and morphology of droplet penetrating a soap film

2021 ◽  
Vol 933 ◽  
Author(s):  
Yanju Wei ◽  
Zhiqiang Mu ◽  
Yajie Zhang ◽  
Yajing Yang ◽  
Shenghua Liu ◽  
...  
Keyword(s):  
Surface Wave ◽  
Experimental Observation ◽  
Weber Number ◽  
Soap Solution ◽  
Soap Film ◽  
Theoretical Explanation ◽  
Physical Models ◽  
Droplet Radius ◽  
Number Range ◽  
Analytical Expressions

This work reports experimental observation and theoretical explanation of the dynamics and morphology of a droplet passing through a soap film. During the process, the film undergoes four sequential responses: (1) film deformation upon droplet impact; (2) drop–film detachment; (3) coalescence of the film shell with the drop; (4) peel-off of the film shell. Physical models and the corresponding analytical expressions are developed to reveal the underlying physics for the observed four responses. It is identified that the film is an elongated catenoid under continuous stretch by the droplet, and that they separate at the fixed height of 5.8 times of the droplet radius while the detach point is located at the centre of the height. After separation, the droplet is wrapped with a film shell, which is then punctured by the ring tip of the converging surface wave at the impacting Weber number range of [45, 225]. The film shell then coalesces with the droplet, falls off with a fixed velocity and is eventually ejected as a bubble leaving the droplet with a transplanted surface of the soap solution.

scholarly journals Breakup of the Water Sheet Formed by Two Liquid Impinging Jets

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Yakang Xia ◽  
Lyes Khezzar ◽  
Shrinivas Bojanampati ◽  
Arman Molki
Keyword(s):  
Weber Number ◽  
Reynolds Numbers ◽  
Impinging Jets ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Impingement Angle ◽  
Number Range ◽  
Breakup Length ◽  
Sheet Breakup ◽  
Visualization Experiments

Flow visualization experiments are carried out to study the flow regimes and breakup length of the water sheet generated by two impinging liquid jets from an atomizer made of two identical tubes 0.686 mm in diameter. These experiments cover liquid jet Reynolds numbers based on the pipe diameter in the range of 1541 to 5394. The effects of the jet velocities and impingement angle between the two jets on the breakup performance are studied. Four spray patterns are recognized, which are presheet formation, smooth sheet, ruffled sheet, and open-rim sheet regimes. Water sheet breakup length is found to be consistent with previous experimental and theoretical results in the lower Weber number (based on water jet diameter and velocity) range. In the relatively high Weber number range, the breakup length tends to a constant value with increasing Weber number, and some discrepancies between experimental and theoretical predictions do exist. Measured water sheet area increases with increasing liquid jet Reynolds numbers and impingement angle within the range of the current study.

Coalescence and separation in binary collisions of liquid drops

1990 ◽  
Vol 221 ◽  
pp. 183-204 ◽  
Author(s):  
N. Ashgriz ◽  
J. Y. Poo
Keyword(s):  
Weber Number ◽  
Theoretical Models ◽  
Binary Collision ◽  
Collision Dynamics ◽  
Number Range ◽  
Liquid Drops ◽  
Binary Collisions ◽  
Different Types ◽  
Large Impact Parameter ◽  
Water Drops

An extensive experimental investigation of the binary collision dynamics of water drops for size ratios of 1. 0.75, and 0.5, for the Weber-number range of 1 to 100, and for all impact parameters is reported. Two different types of separating collisions, namely reflexive and stretching separations, are identified. Reflexive separation is found to occur for near head-on collisions, while stretching separation occurs for large-impact-parameter collisions. The boundaries between both of the separating collisions and coalescence collision are found experimentally. Theoretical models for predictions of the reflexive and stretching separation are also given.

scholarly journals Secondary breakup of a drop at moderate Weber numbers

2015 ◽  
Vol 471 (2177) ◽  
pp. 20140930 ◽  
Author(s):  
Mohit Jain ◽  
R. Surya Prakash ◽  
Gaurav Tomar ◽  
R. V. Ravikrishna
Keyword(s):  
Numerical Simulations ◽  
Lognormal Distribution ◽  
Weber Number ◽  
Drop Size ◽  
Density Ratio ◽  
Transition Regime ◽  
Number Range ◽  
High Density Ratio ◽  
Secondary Breakup ◽  
Good Agreement

We present volume of fluid based numerical simulations of secondary breakup of a drop with high density ratio (approx. 1000) and also perform experiments by injecting monodisperse water droplets in a continuous jet of air and capture the breakup regimes, namely, bag formation, bag-stamen, multibag and shear breakup, observed in the moderate Weber number range (20–120). We observe an interesting transition regime between bag and shear breakup for We =80, in both simulations as well as experiments, where the formation of multiple lobes, is observed, instead of a single bag, which are connected to each other via thicker rim-like threads that hold them. We show that the transition from bag to shear breakup occurs owing to the rim dynamics which shows retraction under capillary forces at We =80, whereas the rim is sheared away with flow at We =120 thus resulting in a backward facing bag. The drop characteristics and timescales obtained in simulations are in good agreement with experiments. The drop size distribution after the breakup shows bimodal nature for the single-bag breakup mode and a unimodal nature following lognormal distribution for higher Weber numbers.

scholarly journals Самоиндуцированная прозрачность в монослое черного фосфора

2018 ◽  
Vol 44 (8) ◽  
pp. 77
Author(s):  
Г.Т. Адамашвили
Keyword(s):  
Surface Wave ◽  
Pulse Propagation ◽  
Optical Soliton ◽  
Black Phosphorus ◽  
Two Dimensional ◽  
Two Dimensional Materials ◽  
Soliton Amplitude ◽  
Induced Transparency ◽  
Analytical Expressions ◽  
Armchair Direction

AbstractA theory of the optical soliton of self-induced transparency (SIT) in a black phosphorus monolayer (phosphorene) has been developed. Explicit analytical expressions describing the surface soliton in phosphorene and other anisotropic two-dimensional materials are obtained. It is shown that the anisotropic phosphorene conductivity leads to exponential damping of the amplitude of the soliton of the surface wave, which strongly depends on the direction of pulse propagation. The maximum damping of the SIT soliton amplitude takes place in the “armchair” direction of phosphorene.

The TAR Model for Calculation of Droplet/Wall Impingement

1998 ◽  
Vol 120 (3) ◽  
pp. 593-597 ◽  
Author(s):  
Haitao Xu ◽  
Yongchang Liu ◽  
Ping He ◽  
Haiqing Wang
Keyword(s):  
Weber Number ◽  
Experimental Results ◽  
Droplet Radius ◽  
Hydrodynamic Behavior ◽  
New Model ◽  
Wall Impingement ◽  
Critical Weber Number ◽  
Wall Interaction

In this paper, we present a new model, called the TAR model, for calculation of droplet/wall impingement. Using this model, we find that the critical Weber number for rebound is not a constant. It varies with the droplet radius. For large drops, the critical Weber numbers and rebound velocities predicted by the TAR model agree with experimental results very well. Whereas, the predicted hydrodynamic behavior of small droplets is very different from that of large drops. This conclusion is significant for modeling engine spray/wall interaction.

scholarly journals Analytical Solutions of the Supersaturation Equation for a Warm Cloud

2016 ◽  
Vol 73 (9) ◽  
pp. 3453-3465 ◽  
Author(s):  
B. J. Devenish ◽  
K. Furtado ◽  
D. J. Thomson
Keyword(s):  
Vertical Velocity ◽  
Numerical Solutions ◽  
Approximate Solutions ◽  
Droplet Radius ◽  
Scaling Relation ◽  
Number Density ◽  
Initial Droplet ◽  
Warm Cloud ◽  
Small Times ◽  
Analytical Expressions

Abstract Approximate solutions of the supersaturation equation are derived for a warm cloud. These solutions take account of the growth of the droplet radius but are only valid for small times. However, the validity of the solutions extends far enough to obtain reasonable estimates of the maximum supersaturation smax. It is shown that when the initial droplet radius and supersaturation are sufficiently small the scaling relation smax ∝ w3/4N−1/2 is obtained, where w is the vertical velocity and N is the droplet number density, in agreement with previous results. The range of validity of this result is discussed and other analytical expressions are derived when this result is not valid. It is shown that these analytical expressions generally agree well with numerical solutions.

scholarly journals Small-amplitude perturbations of shape for a nearly spherical bubble in an inviscid straining flow (steady shapes and oscillatory motion)

1988 ◽  
Vol 187 ◽  
pp. 231-266 ◽  
Author(s):  
I. S. Kang ◽  
L. G. Leal
Keyword(s):  
Steady State ◽  
Weber Number ◽  
Ad Hoc ◽  
Steady State Solution ◽  
Oscillatory Motion ◽  
Frequency Change ◽  
Number Range ◽  
Spherical Bubble ◽  
Critical Weber Number ◽  
Domain Perturbations

The method of domain perturbations is used to study the problem of a nearly spherical bubble in an inviscid, axisymmetric straining flow. Steady-state shapes and axisymmetric oscillatory motions are considered. The steady-state solutions suggest the existence of a limit point at a critical Weber number, beyond which no solution exists on the steady-state solution branch which includes the spherical equilibrium state in the absence of flow (e.g. the critical value of 1.73 is estimated from the third-order solution). In addition, the first-order steady-state shape exhibits a maximum radius at θ = ⅙π which clearly indicates the barrel-like shape that was found earlier via numerical finite-deformation theories for higher Weber numbers. The oscillatory motion of a nearly spherical bubble is considered in two different ways. First, a small perturbation to a spherical base state is studied with the ad hoc assumption that the steady-state shape is spherical for the complete Weber-number range of interest. This analysis shows that the frequency of oscillation decreases as Weber number increases, and that a spherical bubble shape is unstable if Weber number is larger than 4.62. Secondly, the correct steady-state shape up to O(W) is included to obtain a rigorous asymptotic formula for the frequency change at small Weber number. This asymptotic analysis also shows that the frequency decreases as Weber number increases; for example, in the case of the principal mode (n = 2), ω2 = ω00(1−0.31W), where ω0 is the oscillation frequency of a bubble in a quiescent fluid.

Satellite formation and merging in liquid jet breakup

1991 ◽  
Vol 433 (1888) ◽  
pp. 269-286 ◽  
Keyword(s):  
Weber Number ◽  
High Speed ◽  
Drop Size ◽  
Liquid Jet ◽  
Number Range ◽  
Satellite Formation ◽  
Long Wavelength ◽  
Breakup Mechanism ◽  
Jet Breakup ◽  
New Type

An experimental investigation of the breakup of a liquid jet using high-speed motion pictures has revealed many different breakup mechanisms. The influence of disturbance amplitude and frequency on the breakup mechanism for a Weber number range of 25 to 160 is considered. The jet breakup is grouped into several distinct regions, depending on the disturbance wavelength ( λ ), and the undisturbed jet diameter ( D ). These include the random breakup region for λ/D < 3, short wavelength Rayleigh breakup region for 3 < λ/D < 5.5, medium wavelength Rayleigh breakup region for 5.5 < λ/D < 11, and long wavelength Rayleigh breakup region for λ/D > 11. Except for the random region ( λ/D < 3), all the other regions show repeatable patterns of breakup. The boundaries between some of the distinct patterns are obtained for various Weber numbers and disturbance amplitudes. A new type of satellite merge is also discovered which is referred to as the reflexive merging satellite. Other features of the jet breakup, such as satellite/drop size ratio and breakup times, are also considered in detail.

scholarly journals Investigation on Surface Wave Characteristic of Water Jet

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
He Jie ◽  
Wang Jingjing ◽  
Liu Xiumei ◽  
Li Beibei ◽  
Li Wei ◽  
...  
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Weber Number ◽  
Water Jet ◽  
Small Scale ◽  
Horizontal Gradient ◽  
Surface Stability ◽  
Wave Characteristic ◽  
The Relationship ◽  
Jet Images

Water jet surface stability is important to enhance fighting efficiency of fire water monitor. In this paper, a visualization experimental method is designed to capture the surface waves of water jet out from fire water monitor, and the wavelength and the amplitudes are captured and measured from the obtained water jet images. The Sobel horizontal gradient direction template and Burg method are selected to obtain wavelength characteristic of water jet. Based on surface morphology, the relationship between wave characteristic of water jet and Weber number is also discussed. The structure of the surface wave changes from cosmic turbulence to stochastic small-scale waves with increasing Weber number and becomes fully chaotic finally. The average wavelength of water jet out from fire water monitor decreases with increasing Weber number. The growth rate in the presence of wavelength with the lower Weg is less than that of the higher Weg. Furthermore, the amplitudes of the water jet increase continuously with increasing flow distance and Weg. In other words, the larger the Weber number is, the faster the velocity of surface waves on water jet is. The main objective of the present work is to give the basis for better understanding the microstructure of water jet, which in turn improves the performance of fire water monitor.

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