scholarly journals The breakup of levitating water drops observed with a high speed camera

2011 ◽  
Vol 11 (19) ◽  
pp. 10205-10218 ◽  
Author(s):  
C. Emersic ◽  
P. J. Connolly
Keyword(s):  
Size Distribution ◽  
High Speed ◽  
Drop Size ◽  
Initial Conditions ◽  
Water Drop ◽  
Liquid Water Content ◽  
Drop Size Distribution ◽  
High Speed Camera ◽  
Size Distributions ◽  
Drop Size Distributions

Abstract. Collision-induced water drop breakup in a vertical wind tunnel was observed using a high speed camera for interactions between larger drop sizes (up to 7 mm diameter) than have previously been experimentally observed. Three distinct collisional breakup types were observed and the drop size distributions from each were analysed for comparison with predictions of fragment distributions from larger drops by two sets of established breakup parameterisations. The observations showed some similarities with both parameterisations but also some marked differences for the breakup types that could be compared, particularly for fragments 1 mm and smaller. Modifications to the parameterisations are suggested and examined. Presented is also currently the largest dataset of bag breakup distributions observed. Differences between this and other experimental research studies and modelling parameterisations, and the associated implications for interpreting results are discussed. Additionally, the stochastic coalescence and breakup equation was solved computationally using a breakup parameterisation, and the evolving drop-size distribution for a range of initial conditions was examined. Initial cloud liquid water content was found to have the greatest influence on the resulting distribution, whereas initial drop number was found to have relatively little influence. This may have implications when considering the effect of aerosol on cloud evolution, raindrop formation and resulting drop size distributions. Calculations presented show that, using an ideal initial cloud drop-size distribution, ~1–3% of the total fragments are contributed from collisional breakup between drops of 4 and 6 mm.

Drop Size Distributions in Oil Water Mixtures

1973 ◽  
Vol 1973 (1) ◽  
pp. 457-465 ◽  
Author(s):  
Vijay K. Stokes ◽  
Andrew C. Harvey
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Standard Procedure ◽  
Drop Size Distribution ◽  
Coulter Counter ◽  
Size Distributions ◽  
Oil Water ◽  
Drop Size Distributions

ABSTRACT The oil drop size distribution in oil water mixtures is of importance in the design of separators that make use of settling or enhanced settling as in centrifuges. This paper describes an attempt to identify the parameters that affect the size distribution of drops in mechanically generated emulsions. Oil/water mixtures were made by three different methods. On the basis of the results of these tests, a standard procedure for making mixtures was adopted. This paper presents the results of an extensive series of tests, with three different oils, in which the drop size distributions were measured by a Coulter Counter.

Using maximum entropy approach for prediction of drop size distribution in a pilot plant multi-impeller extraction contactor

RSC Advances ◽  
2015 ◽  
Vol 5 (116) ◽  
pp. 95967-95980 ◽  
Author(s):  
Mehdi Asadollahzadeh ◽  
Meisam Torab-Mostaedi ◽  
Shahrokh Shahhosseini ◽  
Ahad Ghaemi
Keyword(s):  
Maximum Entropy ◽  
Size Distribution ◽  
Pilot Plant ◽  
Drop Size ◽  
Maximum Entropy Principle ◽  
Drop Size Distribution ◽  
Size Distributions ◽  
Entropy Principle ◽  
Drop Size Distributions ◽  
Column Extractor

In this study, the maximum entropy principle is used to predict the drop size distributions in a multi-impeller column extractor.

scholarly journals Drop Size Distribution Measurements in Outer Rainbands of Hurricane Dorian at the NASA Wallops Precipitation-Research Facility

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 578 ◽  
Author(s):  
Merhala Thurai ◽  
Viswanathan N. Bringi ◽  
David B. Wolff ◽  
David A. Marks ◽  
Charanjit S. Pabla
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Drop Size Distribution ◽  
Size Distributions ◽  
Research Facility ◽  
Bright Band ◽  
Wet Snow ◽  
Double Moment ◽  
Dominant Process ◽  
Drop Size Distributions

Hurricane rainbands are very efficient rain producers, but details on drop size distributions are still lacking. This study focuses on the rainbands of hurricane Dorian as they traversed the densely instrumented NASA precipitation-research facility at Wallops Island, VA, over a period of 8 h. Drop size distribution (DSD) was measured using a high-resolution meteorological particle spectrometer (MPS) and 2D video disdrometer, both located inside a double-fence wind shield. The shape of the DSD was examined using double-moment normalization, and compared with similar shapes from semiarid and subtropical sites. Dorian rainbands had a superexponential shape at small normalized diameter values similar to those of the other sites. NASA’s S-band polarimetric radar performed range height-indicator (RHI) scans over the disdrometer site, showing some remarkable signatures in the melting layer (bright-band reflectivity peaks of 55 dBZ, a dip in the copolar correlation to 0.85 indicative of 12–15 mm wet snow, and a staggering reflectivity gradient above the 0 °C level of −10 dB/km, indicative of heavy aggregation). In the rain layer at heights < 2.5 km, polarimetric signatures indicated drop break-up as the dominant process, but drops as large as 5 mm were detected during the intense bright-band period.

Controls on the space-time variability of raindrop size distributions

2021 ◽  
Author(s):  
Remko Uijlenhoet
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Space Time ◽  
Drop Size Distribution ◽  
Time Variability ◽  
Statistical Interpretation ◽  
Size Distributions ◽  
Scaling Exponents ◽  
Raindrop Size ◽  
Drop Size Distributions

&lt;p&gt;It has been stated that &quot;the study of drop-size distributions, with its roots in both land-surface processes [e.g. interception, erosion, infiltration and surface runoff] and atmospheric remote sensing [e.g. radar meteorology], provides an important element to an integrated program of hydrometeorological research&quot; (Smith, 1993). Although raindrop size distributions have been studied from a scientific perspective since the early 20th century, it was not until the mid-1990s that researchers realized that all parameterizations for the drop size distribution published until then could be summarized in the form of a scaling law, which provided &quot;a general phenomenological formulation for drop size distribution&quot; (Sempere Torres et al., 1994). The main implication of the proposed expression is that the integral rainfall variables (such as rain rate and radar reflectivity) are related by power laws, in agreement with experimental evidence. The proposed formulation naturally leads to a general methodology for scaling all raindrop size data in a unique plot, which yields more robust fits of the drop size distribution. Here, we provide a statistical interpretation of the law&amp;#8217;s scaling exponents in terms of different modes of control on the space-time variability of drop size distributions, namely size-control vs. number-control, inspired by the work of Smith and De Veaux (1994). Also, an attempt will be made toward interpreting the values of the scaling exponents and the shape of the scaled drop size distribution in terms of the underlying (micro)physical processes.&lt;/p&gt;&lt;p&gt;REFERENCES&lt;/p&gt;&lt;p&gt;Smith, J. A., 1993: Precipitation. In Maidment, D. R., editor, Handbook of Hydrology, pages 3.1&amp;#8211;3.47. McGraw-Hill, New York.&lt;/p&gt;&lt;p&gt;Sempere Torres, D., J.M. Porr&amp;#224;, and J.-D. Creutin, 1994: A general formulation for raindrop size distribution. J. Appl. Meteor., 33, 1494&amp;#8211;1502.&lt;/p&gt;&lt;p&gt;Smith, J.A. and R.D. De Veaux, 1994: A stochastic model relating rainfall intensity to raindrop processes. Water Resour. Res., 30, 651&amp;#8211;664.&lt;/p&gt;

MEASUREMENTS OF CLOUD DROP-SIZE DISTRIBUTIONS

1957 ◽  
Vol 14 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Ralph G. Eldridge
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Drop Size Distribution ◽  
Size Distributions ◽  
Cloud Drop ◽  
Infrared Transmittance ◽  
Drop Size Distributions ◽  
Visual Range ◽  
Mount Washington

Abstract Through the analysis of infrared transmittance of a natural cloud, its drop-size distribution can be inferred. This technique has been used to measure and analyze ten cloud situations on Mount Washington. These clouds show drop-size distributions that are bimodal in character. In all the distributions, a large number of small droplets is inferred. To test the synthesized distributions in another region of the spectrum, the visual range was computed. This determination of the visual range is in agreement with the observed visibilities.

Drop size distributions by power functions of breakage and coalescence

1982 ◽  
Vol 47 (9) ◽  
pp. 2393-2402 ◽  
Author(s):  
Helena Sovová
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Direct Determination ◽  
Drop Size Distribution ◽  
Size Distributions ◽  
Power Functions ◽  
Drop Size Distributions ◽  
Drop Breakage ◽  
Batch Mixer

The frequencies of drop breakage and coalescence in a batch mixer are described by power functions of drop sizes. The shape of a steady state drop size distribution corresponding to the power functions is correlated with their exponents. The use of this correlation for direct determination of linear combination of power functions exponents from an experimental drop size distribution is demonstrated.

Drop-Size Distribution Measurements in Orographic Rain

1948 ◽  
Vol 29 (7) ◽  
pp. 362-366 ◽  
Author(s):  
Lloyd J. Anderson
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Rainfall Intensity ◽  
Drop Size Distribution ◽  
Similar Data ◽  
Size Distributions ◽  
Similarities And Differences ◽  
Drop Size Distributions

Measurements on rainfall near Hilo, Hawaii are described. Quartile deviations of drop-size distributions are plotted versus rainfall intensity. Comparison is made with similar data of Laws and Parsons, and certain similarities and differences are pointed out.

Drop-Size Distributions of Bingham Liquid (PAINT) Sprays Produced by Fan-Jet Pressure Nozzles

1979 ◽  
Vol 101 (4) ◽  
pp. 449-455
Author(s):  
W. S. Janna ◽  
J. E. A. John
Keyword(s):  
Shear Stress ◽  
Size Distribution ◽  
Drop Size ◽  
Drop Size Distribution ◽  
Size Distributions ◽  
Collection Device ◽  
Median Diameter ◽  
Drop Size Distributions ◽  
Liquid Paint ◽  
Microscope Slides

The drop-size distribution of Bingham liquid sprays was determined by experimentation. Three different highly viscous paints were sprayed with fan-jet airless spray nozzles at pressure ranging from 5 170 to 18 200 kPa. A collection device was constructed to capture a spray sample on microscope slides. Measurement of flattened droplet diameters with a microscope yielded drop-size distribution curves of accumulated volume per cent versus volume median diameter. It was postulated that the wall shear stress existing at the exit plane of the nozzle initiated liquid atomization. A logarithmic correlation was found between shear stress and volume median diameter.

Drop-Size Distributions of Newtonian and Bingham Liquid Sprays Produced by Fan-Jet Pressure Nozzles With and Without the Preorifice

1981 ◽  
Vol 103 (4) ◽  
pp. 402-408
Author(s):  
William S. Janna ◽  
James E. A. John
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Drop Size Distribution ◽  
Distribution Data ◽  
Size Distributions ◽  
Volume Percent ◽  
Collection Device ◽  
Drop Size Distributions ◽  
Microscope Slides ◽  
Pressure Nozzle

Measurements were made of the drop-size distributions of water and of paint sprays produced by fan-jet pressure nozzles, operating in the pressure range 900 to nearly 3000 psi (6200–20,680 kPa). A collection device was constructed and droplets were captured on soot-coated and on plain microscope slides. Subsequent sizing of the impacted particles with a microscope yielded drop-size distribution data of accumulated volume percent versus diameter. Data were gathered of water and of paint sprays produced by a fan-jet pressure nozzle-preorifice combination. The effect of the preorifice on drop-size distribution was evaluated.

scholarly journals Raindrop Size Distribution and Rain Characteristics during the 2013 Great Colorado Flood

2015 ◽  
Vol 17 (1) ◽  
pp. 53-72 ◽  
Author(s):  
Katja Friedrich ◽  
Evan A. Kalina ◽  
Joshua Aikins ◽  
Matthias Steiner ◽  
David Gochis ◽  
...  
Keyword(s):  
Drop Size ◽  
Doppler Radar ◽  
Liquid Water Content ◽  
Size Distributions ◽  
Intense Rainfall ◽  
Wind Fields ◽  
Raindrop Size Distribution ◽  
Median Volume ◽  
Drop Size Distributions ◽  
Analysis System

Abstract Drop size distributions observed by four Particle Size Velocity (PARSIVEL) disdrometers during the 2013 Great Colorado Flood are used to diagnose rain characteristics during intensive rainfall episodes. The analysis focuses on 30 h of intense rainfall in the vicinity of Boulder, Colorado, from 2200 UTC 11 September to 0400 UTC 13 September 2013. Rainfall rates R, median volume diameters D0, reflectivity Z, drop size distributions (DSDs), and gamma DSD parameters were derived and compared between the foothills and adjacent plains locations. Rainfall throughout the entire event was characterized by a large number of small- to medium-sized raindrops (diameters smaller than 1.5 mm) resulting in small values of Z (&lt;40 dBZ), differential reflectivity Zdr (&lt;1.3 dB), specific differential phase Kdp (&lt;1° km−1), and D0 (&lt;1 mm). In addition, high liquid water content was present throughout the entire event. Raindrops observed in the plains were generally larger than those in the foothills. DSDs observed in the foothills were characterized by a large concentration of small-sized drops (d &lt; 1 mm). Heavy rainfall rates with slightly larger drops were observed during the first intense rainfall episode (0000–0800 UTC 12 September) and were associated with areas of enhanced low-level convergence and vertical velocity according to the wind fields derived from the Variational Doppler Radar Analysis System. The disdrometer-derived Z–R relationships reflect how unusual the DSDs were during the 2013 Great Colorado Flood. As a result, Z–R relations commonly used by the operational NEXRAD strongly underestimated rainfall rates by up to 43%.

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