High framing rate PIV studies of an impinging water drop

2008 ◽  
Author(s):  
J.-L. Liow ◽  
D. E. Cole
Keyword(s):  
Water Drop ◽  
Framing Rate

Reply to “Comments on ‘Energy Dissipation During Water Drop Impact In Shallow Pools’”

1986 ◽  
Vol 50 (6) ◽  
pp. 1644-1645
Author(s):  
Alfredo G. Ferreira ◽  
Bruce E. Larock ◽  
Michael J. Singer
Keyword(s):  
Energy Dissipation ◽  
Water Drop ◽  
Drop Impact

EVALUATING STABILITY OF FOUNDATION AROUND WATER DROP WORKS WITH A HYDRAULIC-GEOTECHNICAL COMBINED METHOD

2018 ◽  
Vol 74 (5) ◽  
pp. I_655-I_660
Author(s):  
Hongxuan YANG ◽  
Yutaka FUKUMOTO ◽  
Tokuzo HOSOYAMADA ◽  
Satoru OHTSUKA
Keyword(s):  
Water Drop ◽  
Combined Method

scholarly journals Ice Coverage Induced by Depositing a Water Drop onto the Supercooled Substrate at Extreme Low Vapor Pressure

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 691
Author(s):  
Yugang Zhao ◽  
Zichao Zuo ◽  
Haibo Tang ◽  
Xin Zhang
Keyword(s):  
Vapor Pressure ◽  
Substrate Temperature ◽  
Water Drop ◽  
Industrial Processes ◽  
Aircraft Icing ◽  
Ice Coverage ◽  
Fundamental Understanding ◽  
Order Of Magnitude ◽  
The Impact ◽  
Kinetics Of

Icing/snowing/frosting is ubiquitous in nature and industrial processes, and the accretion of ice mostly leads to catastrophic consequences. The existing understanding of icing is still limited, particularly for aircraft icing, where direct observation of the freezing dynamics is inaccessible. In this work, we investigate experimentally the impact and freezing of a water drop onto the supercooled substrate at extremely low vapor pressure, to mimic an aircraft passing through clouds at a relatively high altitude, engendering icing upon collisions with pendant drops. Special attention is focused on the ice coverage induced by an impinging drop, from the perimeter pointing outward along the radial direction. We observed two freezing regimes: (I) spread-recoil-freeze at the substrate temperature of Ts = −15.4 ± 0.2 °C and (II) spread (incomplete)-freeze at the substrate temperature of Ts = −22.1 ± 0.2 °C. The ice coverage is approximately one order of magnitude larger than the frozen drop itself, and counterintuitively, larger supercooling yields smaller ice coverage in the range of interest. We attribute the variation of ice coverage to the kinetics of vapor diffusion in the two regimes. This fundamental understanding benefits the design of new anti-icing technologies for aircraft.

scholarly journals Spreading and Drying Dynamics of Water Drop on Hot Surface of Superwicking Ti-6Al-4V Alloy Material Fabricated by Femtosecond Laser

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 899
Author(s):  
Ranran Fang ◽  
Zekai Li ◽  
Xianhang Zhang ◽  
Xiaohui Zhu ◽  
Hanlin Zhang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Surface Structure ◽  
Energy Savings ◽  
Water Drop ◽  
Capillary Surface ◽  
Water Flow Velocity ◽  
Capillary Action ◽  
Practical Applications ◽  
Alloy Material ◽  
Hot Surface

A superwicking Ti-6Al-4V alloy material with a hierarchical capillary surface structure was fabricated using femtosecond laser. The basic capillary surface structure is an array of micropillars/microholes. For enhancing its capillary action, the surface of the micropillars/microholes is additionally structured by regular fine microgrooves using a technique of laser-induced periodic surface structures (LIPSS), providing an extremely strong capillary action in a temperature range between 23 °C and 80 °C. Due to strong capillary action, a water drop quickly spreads in the wicking surface structure and forms a thin film over a large surface area, resulting in fast evaporation. The maximum water flow velocity after the acceleration stage is found to be 225–250 mm/s. In contrast to other metallic materials with surface capillarity produced by laser processing, the wicking performance of which quickly degrades with time, the wicking functionality of the material created here is long-lasting. Strong and long-lasting wicking properties make the created material suitable for a large variety of practical applications based on liquid-vapor phase change. Potential significant energy savings in air-conditioning and cooling data centers due to application of the material created here can contribute to mitigation of global warming.

scholarly journals Strain-dependent wicking behavior of cotton/lycra elastic woven fabric for sportswear

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 263-271
Author(s):  
Yong Wang ◽  
Qifan Qiao ◽  
Zuowei Ding ◽  
Fengxin Sun
Keyword(s):  
Tensile Strain ◽  
Water Drop ◽  
Woven Fabric ◽  
Strengthening Effect ◽  
Wetting Time ◽  
Horizontal Wicking ◽  
Different Strains ◽  
Strain Dependent ◽  
Different Levels ◽  
Strain Strengthening

Abstract The strain-dependent vertical and horizontal wicking of as-prepared cotton/lycra elastic woven fabric was systematically studied. The experimental results revealed that the fabric exhibited a strain strengthening effect. A higher tensile strain results in a higher equilibrium wicking height, and vice versa. Moreover, the results indicated that the proposed Laughlin–Davies model is capable of tracking well the experimental data and replicating the wicking characteristics of fabric under different levels of stretch. In addition, the wetting time and wicking area of fabric under different strains and height regimes were examined during horizontal wicking. It was found that the wetting time decreased with an increase of strain and/or water drop height. The strain-enhanced and height-weakened effects of wicking area were revealed. The spreading mechanism of water drop in elastic fabric was also proposed. Such fundamental work provides a basic support for the in-depth investigation of wicking behavior of complex stretchable textile structures.

A Water-Drop Method of Hardening of the Welded Joints of Drill Pipes

2015 ◽  
Vol 57 (5-6) ◽  
pp. 295-299
Author(s):  
M. V. Maisuradze ◽  
Yu. V. Yudin ◽  
Yu. G. Eismondt
Keyword(s):  
Welded Joints ◽  
Water Drop ◽  
Drop Method ◽  
Drill Pipes

Soil water repellency persistence after recurrent forest fires on Mount Carmel, Israel

2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Forest Fires ◽  
Water Drop ◽  
Chemical Properties ◽  
Water Repellency ◽  
Mediterranean Ecosystem ◽  
Long Term Effects ◽  
Soil Water Repellency ◽  
Chemical Properties Of Soils

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.

Splash formation by spherical drops

2001 ◽  
Vol 427 ◽  
pp. 73-105 ◽  
Author(s):  
LIOW JONG LENG
Keyword(s):  
High Resolution ◽  
Quantitative Data ◽  
Water Surface ◽  
High Speed ◽  
Scaling Laws ◽  
Capillary Wave ◽  
Water Drop ◽  
Qualitative And Quantitative ◽  
High Resolution Images ◽  
The Impact

The impact of a spherical water drop onto a water surface has been studied experimentally with the aid of a 35 mm drum camera giving high-resolution images that provided qualitative and quantitative data on the phenomena. Scaling laws for the time to reach maximum cavity sizes have been derived and provide a good fit to the experimental results. Transitions between the regimes for coalescence-only, the formation of a high-speed jet and bubble entrapment have been delineated. The high-speed jet was found to occur without bubble entrapment. This was caused by the rapid retraction of the trough formed by a capillary wave converging to the centre of the cavity base. The converging capillary wave has a profile similar to a Crapper wave. A plot showing the different regimes of cavity and impact drop behaviour in the Weber–Froude number-plane has been constructed for Fr and We less than 1000.

Collisions between liquid drops

1978 ◽  
Vol 287 (1349) ◽  
pp. 635-675 ◽  
Keyword(s):  
Simple Model ◽  
Impact Parameter ◽  
Water Drop ◽  
Free Fall ◽  
Electrostatic Energy ◽  
Good Effect ◽  
Frequency Distributions ◽  
Input Parameters ◽  
The Impact ◽  
Drop Charge

An experiment is described in which pairs of water drops of different size were caused to collide during free fall at a velocity equal to the difference of their terminal velocities in still air. The collision parameters of trajectory, drop size, and drop charge were controlled with precision, and impacts of a particular kind could be reproduced indefinitely. By using synchronized flash photography, well in excess of 30000 measurements were taken from more than 10000 frames of film of the resulting behaviour of the water-drop pairs. Data are discussed in terms of an impact parameter, X which defines the relative trajectory of the drops in the centre-of-mass frame, and three energy parameters e C , e R and e T which delineate the properties electrostatic energy, rotational energy, and total energy of the two-drop system before impact. Input parameters were confined to values appropriate to natural rainfall. After collision four basic types of rotation occurred, the particular kind of rotation depending upon X , e C , e R and e T . Measured rates of rotation were compared with that to be expected from a simple model of inelastic collision between solid spheres and showed a marked resemblance. Distributions of mass after collision were compared with a model based upon a bimodal Gaussian distribution to good effect. In addition, frequency distributions of the number of drop products resulting from a given collision were prepared showing the controlling influence of the impact parameter, X , and the effect of varying drop charge. Relations were also established between statistical values for the coalescence efficiency of a given drop pair and the input parameters; however, while all results were consistent and reproducible, the effect of drop charge could not be demonstrated by a simple model.

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