SCIENTIFIC ABSTRACT TVERSKOY, N.P. - TVERSKOY, N.P.

• Document Type: CREST
• Collection: Scientific Abstracts
• Document Number (FOIA) /ESDN (CREST): CIA-RDP86-00513R001757630005-7
• Release Decision: RIF
• Original Classification: S
• Document Page Count: 5
• Document Creation Date: November 2, 2016
• Document Release Date: April 3, 2001
• Sequence Number: 5
• Publication Date: December 31, 1967
• Content Type: SCIENTIFIC ABSTRACT

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ACCESSION N2: AT4011392 8/2531/63/000/145/006/0043
AUMOR: Tvorskoy, H. P.
TITLE: The problem of coagulation of fog droplets by sonic oncillbtions,
SOURCE: Leningrad. Glavna-va geofizicheakaya'obseiriatoriyek. True-A, no. 145,
1963. Voprosy-* fiziki oblakov i aktivny-*kh vozdey~tvin 36-48
TOPIC TAGS: meteorology, fog, droplet coagalatian, sonic oscillabiong fog die-
persal, weather modification
ABSTRACT: The mechanism of coagulation of fog droplets under the influenco of
sonic oscillations is reviewed. The orthokinetic theory cannot explain this Me-
chanism. The difference in the amplitudes of oscillation of droplets of various
sizes c-not be responsible for the fusion of droplets because the distance be-
tween droplets at a liquid water content v - 0.1 j/m3 is greater than the dif-
ference in the amplitudes of oscillation. This theory applies cznly vhen droplets
already have regrouped under the influence of sonic oscillations aud converge to
distances comparable to the amplitude of oscillation under the influence of other
cesses. According to.the hydrodynamic theory, droplet cosgulatioa increases
pro
with an increaae in the dimension of droplets and increases -ith an Increase *f
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~ACCESSION NR: AT4011392
!the frequency of sonic oscillations (to a certain limit). With'an increase of
.sonic intensity the effect increases, but to a lesser degree than according to
the orthokinetic theory; coagulation proceeds most intensively when the droplet
density is high. Hydrodynamic forces of interaction, considered together with
.oscillatory motions of fog droplets in a high-frequency sound field, can exert a
substantial influence on coagulation of fog droplets greater than 1 Micron in
diameter. Formulas describing the coagulation of droplets under the influence
of sonic pressure are cited and the effect of intense sonic waves on a fog des-
icribed. The enlargement and falling of droplets in described as follows. In a
field of intense sonic oscillations the droplets come into complex oscillatory
motion. Under the influence of a shock wave they break up into finer droplets.
Some evaporate in the sonic field due to thermal heating and others move perpen-
dicular to the sonic wave front. Near the sonic source the droplets are being
blown away or evaporated continuously. The sonic wave front changes as it moves
and harmonics appear in the propagating frequency which are caused by the pre-
senoo of "broken* droplets in the medium. At a great distance from the source
the droplets, still with oscillatory motion, vill regroup into denser complexes.
Depending on the oscillatory frequency these complexes will have different group-
ings and distances and the droplets ii the complex will begin to fuse and enlarge
.and then fall under the influence of gravity. Hydrodynamic and radiation forces
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ACCESSIO' N NR: AT4011392
also induce a shortening of the distance 4tween droplets and their COAgUlati0a.
These processes are most effective at frequencies of the order of several thou-
sand cycles per necond. Low frequencies are beat for dense fogs. However, be-
pause droplets of various sizes are present the frequency of the sonic oscilla-
'tion3 must be variedwithin certain limits and - artain optimum value must be
seljeted due to the increase of attenuation with increase of sonic frequecay; the
ro~commended range in 1500 to 5000 cps. Sonic oscillations having an intensity at
point of effect of 0.5 watt/cm2 in the indicated frequency range can disperse a
fog in seconds. Orig. art. has: 29 formulas, 3 figures and 2 tables,
ASSOCIATION: Glavnaya geofizichaskaya observateriya, Leningrad (Main Geophysical
Observatory)
SMNIITTED: 00 DATE ACQ: 24Feb64 ENCL: 00
SUB CODE: AS NO REP 86V: 008 otmk 006
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