A Numerical Investigation of the Effect of Electric Charges and Vertical External Electric Fields an the Collision Efficiency of Cloud Drops: Part II

Abstract

Abstract The numerical model of Schlamp et al. (1976) for determining the collision efficiency of electrically charged or unchanged cloud drops in the presence or absence of a vertical electric field has been extended to study the two following cases, both of which include the presence of a vertical field due to a net positive charge in the upper part of the cloud and a net negative charge in the lower part of the cloud: (i) the larger drop is negatively charged and is initially above the smaller drop, which is positively charged; (ii) the larger drop is negatively charged and it is initially below the smaller drop, which is again positively charged. Also, for the purpose of resolving more accurately the critical electric charge on the drops and the critical electric field necessary to significantly affect the collision efficiency, additional computations have been carried out for charged drops in the absence of an electric field and for unchanged drops in the presence of a vertical electric field. The si...