Tables and Graphs for the Settling Velocity of Quartz in Water, Above the Range of Stokes' Law.

摘要

It has been common practice to make mechanical analyses of sediments by various methods. The history and evaluation of methods of mechanical analysis are given by Krumbein (1933) and Krumbein and Pettijohn (1938). One of the most widely used methods, in essence measures the settling velocity of particles in a fluid. An expression of particle size is then computed from the measured rate of setting. Aside from the mechanical problems of getting particles in suspension and measuring their settling velocities this problem seems simple enough at first glance. However, when one looks for ways in which the size can be obtained from a velocity measurement, one is struck by the complexity of the problem and the difficulty of using already prepared tables, graphs or formulas. Some experimental work plus analytical calculations regarding settling velocities for natural materials has been done. Advantage should be taken of published tables for drag coefficients and Reynolds numbers for sand size materials. The theoretical background which follows is a discussion of general fluid properties which affect settling particles.