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Record 7 of 1372
The effects of van der Waals attractions on cloud droplet growth by coalescence
External Online Source: doi:10.1175/1520-0469(1990)047<1075:TEOVDW>2.0.CO;2
Author and Affiliation:
Rogers, Jan R.(Colorado Univ., Boulder, CO, United States)
Davis, Robert H.(Colorado, University, Boulder, United States)
Abstract: The inclusion of van der Waals attractions in the interaction between cloud droplets has been recently shown to significantly increase the collision efficiencies of the smaller droplets. In the current work, these larger values for the collision efficiencies are used in a population dynamics model of the droplet size distribution evolution with time, in hopes of at least partially resolving the long-standing paradox in cloud microphysics that predicted rates of the onset of precipitation are generally much lower than those which are observed. Evolutions of several initial cloud droplet spectra have been tracked in time. Size evolutions are compared as predicted from the use of collision efficiencies computed using two different models to allow for droplet-droplet contact: one which considers slip flow effects only, and one which considers the combined effects of van der Waals forces and slip flow. The rate at which the droplet mass density function shifts to larger droplet sizes is increased by typically 20-25 percent, when collision efficiencies which include van der Waals forces are used.
Publication Date: May 01, 1990
Document ID:
19900051308
(Acquired Nov 28, 1995)
Accession Number: 90A38363
Subject Category: METEOROLOGY AND CLIMATOLOGY
Document Type: Journal Article
Publication Information: Journal of the Atmospheric Sciences (ISSN 0022-4928); 47; 1075-108
Publisher Information: United States
Contract/Grant/Task Num: NAGW-951; NAG3-993
Financial Sponsor: NASA; United States
Organization Source: Colorado Univ.; Boulder, CO, United States
Description: 6p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: CLOUDS (METEOROLOGY); DROP SIZE; DROPS (LIQUIDS); RAIN; VAN DER WAALS FORCES; CONDENSATION NUCLEI; DISTRIBUTION FUNCTIONS
Imprint And Other Notes: Journal of the Atmospheric Sciences (ISSN 0022-4928), vol. 47, May 1, 1990, p. 1075-1080.
Availability Source: Other Sources
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