Free- fall behavior of planar snow crystals, conical graupel and small hail

Abstract

The Reynolds number (RE) range covered for the crystals was 0. 1 to 200 and for the conical models 10 to 2000. It was found that the drag coefficients of dendritic shapes differed by factors of up to 4 from that of a disk of equal thickness and at an equal Reynolds number. The drag ratio is roughly constant with Re and linearly related to the ratio of the respective surface areas. The drag coefficients of the conical models assumed values between 0. 5 and 2. 0.