Semi- empirical determination of the shape of cloud and rain drops

Abstract

A physical model which predicts the shape of water drops falling at terminal velocity in air is presented. The model is based on a balance of the forces which act on a drop falling under gravity in a viscous medium. Calculations of the model are shown to agree with experimental observations. The shape of the water drops of radii between 170 and 4000 U (equivalent to Reynolds numbers between 30 and 4900) was determined.