An experimental study of free fall of cones in Newtonian and Non-Newtonian media: drag coefficient and wall effects

Abstract

The free settling of cones in Newtonian and power law fluids has been investigated experimentally. The extent of wall effects exerted by the cylindrical boundaries has been studied by carrying out experiments in fall tubes of different diameters. The results on wall effects and drag coefficients have been analysed in a manner analogous to those used for spheres. New predictive expressions are developed for both wall effects and drag coefficients in Newtonian as well as non-Newtonian power law fluids. The results reported herein encompass the following ranges of variables: 43° < α < 93.7°; 1 > n > 0.62; 3.73 × 10^-3 < m < 4 Pa sⁿ; 8.24 × 10^-4 < Re_∞ < ~ 500, and 0.148 < d/D < 0.4343. Within the ranges of conditions covered herein, the cone angle does not exert any influence on wall effects or the drag coefficient.