Interactions between Equal-Sized Droplets Due to the Wake Effect

Cataneo, Robert; Adam, John R.; Semonin, Richard G.

doi:10.1175/1520-0469(1971)028<0416:ibesdd>2.0.co;2

Cited by 7 publications

(3 citation statements)

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“…The values of E x , without external electric field, in mustard and kerosene oil media respectively are 0.64 and 7.0. The values of Ex obtained for water drops in mustard oil are in agreement with the theoretically computed values of collision efficiency for cloud drops (Wallace and Hobbs, 1977;Cataneo et al, 1971;Schlamp et al, 1976). The higher values of Ex for water drops in kerosene, exceeding unity could be attributed to the enhanced wake effect (Wallace and Hobbs, 1977).…”

Section: R Rsupporting

confidence: 85%

An experimental investigation of the influence of electric field on the collision-coalescence of water drops

Paul

Selvam

Murty

1979

Tellus A: Dynamic Meteorology and Oceanography

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Laboratory experiments were conducted on the collision-coalescence of pairs of water drops of equal size, in two oil media (kerosene and mustard), with and without external vertical electric field (F). The radii of the water drops used were in the range 1.6 to 1.7 mm and the external electric field varied from 0 to 375 V cm-'. Collision frequencies were determined for various combinations of mean lateral (X) and mean vertical (Z) separations of the drop pairs as fixed combinations of X and Z could not be reproduced in any given set of experiments due to the limitations of the mechanical set up of the apparatus.The collision frequency (E) for any given initial values of X and Z decreased with F up to a certain value of F and thereafter increased. The variations observed in the collision frequency under different external electric fields have been explained quantitatively based on the electrostatic theory of polarization charges. The vertical distance travelled by the pair of drops prior to a collision was less with the external electric field. For collision to occur at a fixed depth (d), the values of Z increased with F when X was zero. For the same initial conditions, collision took place earlier in kerosene than in mustard oil medium. The collision efficiency (Ex), computed from the measured values of the radius of the collisioncross-sectional area, was less in the presence of external electric field. The drops did not coalesce without the external electric field. The coalescence frequency (E,) increased with F. The field values for 100% coalescence were lower in mustard oil as compared to those in kerosene. The path length between collision and coalescence events sharply decreased with increase of F. The collection efficiency was zero without external electric field and it increased with F. In the case where the collected drop was slightly smaller than the collector drop the collection efficiency was more compared to that when the drops were of equal size.

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Section: R Rsupporting

confidence: 85%

An experimental investigation of the influence of electric field on the collision-coalescence of water drops

Paul

Selvam

Murty

1979

Tellus A: Dynamic Meteorology and Oceanography

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“…Experimental measurements of the size of the wake behind drops as small as 50 tt were reported by Cataneo et al [1971]. They observed increases of 1% in the velocity of an equal size downstream drop at vertical separation of 200 radii and horizontal separation of 4-6 radii.…”

Section: Resultsmentioning

confidence: 99%

Experimental cloud droplet collection efficiencies

Abbott¹

1974

J. Geophys. Res.

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“…The vertical separation required for a 1% change in the fall velocity of equal drops 55-350 • in radius has been measured by Cantaneo et al [1970], and the percentage change in velocity as a function of vertical separation for 150-to 250-• drops by Eaton [1970]. The results of these investigations showed that velocities increased about 1% at separations of about 400 radii, and Eaton reported that drops either coalesced or moved out of the wake.…”

Section: Schneider Et Al [1965] Used Highly and Oppositely Charged Dmentioning

confidence: 99%

A survey of Waterdrop Interaction Experiments

Abbott¹

1977

Reviews of Geophysics

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The growth of waterdrops by inertial capture and coalescence induced by the size‐dependent terminal velocities in the earth's gravitational field is an important process in the formation of rain. The extensive experimental data on this fundamental process are reviewed and organized into a coherent summary of the collection efficiencies applicable to natural clouds, in the following circumstances: negligible effects of electric charges and fields, normal laboratory temperatures and pressures, and relative humidities between 50 and 100%. The judgments required to reduce the experimental data to the brief summary form are documented.

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Interactions between Equal-Sized Droplets Due to the Wake Effect

Cited by 7 publications

References 0 publications

An experimental investigation of the influence of electric field on the collision-coalescence of water drops

An experimental investigation of the influence of electric field on the collision-coalescence of water drops

Experimental cloud droplet collection efficiencies

A survey of Waterdrop Interaction Experiments

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