On the Production of Satellite Droplets During Collisions Between Water Drops Failing in Still Air

Abstract

Abstract Data derived from an experimental investigation of the drop collision problem are described in which the numbers of satellite droplets per collision Ng was found. 1026 separate collisions were observed of which 266 resulted in coalescence without breakup, and at least 405 produced the so-called satellite droplets. The value of Ng varied from zero to seven, with average values N?g proving to be a linear function of the collision speed U, where N?g could be predicted by the relationship N?g=3.5 (U?1) if U>1 m s?1. For impact speeds of less than 1 m s?1, negligible number of satellites were produced. It proved impossible to correlate N?g with either the impact parameter or the drop charge, both of which could be accurately controlled, but there appeared to be a dependence of N?g on both a dimensionless parameter of rotational energy and a dimensionless parameter of electrostatic energy for a given collision. The statistical nature of the data is emphasized in relation to computations on raindrop distributions.