Free Settling Cylindrical Particles in Stagnant Water [Translated]†

Abstract

The free settling behavior of cylindrical particles with densities ranging from 1.18 to 8.03 g/cm3 in stagnant water was observed with the aid of cameras and a stroboscope. The particles used ranged from 0.3 to 1.0 cm in diameter, and their size ratios of the diameter to the length were from 1.1 to 9.0. Particles having a size ratio over 1.2 sank with a periodic wobbling motion in the range of 700 to 15000 Reynolds number. This motion was simply expressed by a harmonic equation composed of several parameters. The parameters were expressed as functions of the size ratio, the density ratio between the particle and water and the Reynolds number. In the regular wobbling motion of the particles, the relationship between the drag coefficient and Reynolds number showed a hysteresis loop, of which the ranges of variation depended on the size of the particles, the density ratio and the Reynolds number.† This report was originally printed in J. Soc. Powder Technology, Japan. 27(10), 673-679 (1990) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Powder Technology, Japan.