Cover: Cloud Droplet Coalescence : Effects of the Davis-Sartor Collision Efficiency.

Cloud Droplet Coalescence : Effects of the Davis-Sartor Collision Efficiency.

Published 1967

by M. Warshaw

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A comparison of the effects of Hocking's 1959 theory of cloud droplet coalescence with the new Davis-Sartor theory. Hocking's theory allows no collisions between droplets when both are under 19 microns radius; the Davis-Sartor theory does not have this limitation. In this study, spectra of droplet size were computed according to both theories for two initial distributions of droplets. Results of the Davis-Sartor collision efficiency show no evidence of the 19-micron cutoff and permit slow growth even when all droplets are under 19 microns. When a significant number of droplets are over 19 microns initially, the Davis-Sartor theory does not permit growth as rapid as the Hocking. Both appear to lead to quasi-asymptotic distributions well below the maximum attainable value, which may be due to the arbitrary truncation of the calculation at 65 microns. An appendix describes the variable-step integration procedure used to produce actual error bounds for the numerical solution. 31 pp. Ref.

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