ABSTRACT

H, a measure of the effect of shape upon the settling velocity of a regular rigid convex particle, is synthesized here from two geometric components, a "form" component and a "surface area" component, plus a third non-geometric parameter which is a function of R_s, the Reynolds number of the flow surrounding a sphere with the same volume and density as the particle and settling in the same fluid. Two expressions for the Reynolds number are found, one for the Stokes regime and beyond, through R_s = 4.0, and the other for flow conditions represented by 4.0<=R_s<2,900. These expressions are based upon the published data of several authors for smooth spheres, prolate and oblate ellipsoids, disks, rectangular parallelepipeds, ight circular cylinders, right circular cones base-to-base, and right rectangular pyramids base-to-base. The standard error of estimate for the low velocity regime is about 4 per cent (n = 100); for the high velocity regime it is about 5.5 per cent (n = 112).