Hydrodynamic Drag Force Acting upon a Spherical Particle on a Rough Bed Composed of Identical Particles

Abstract

In order to investigate the characteristics of drag force acting upon a spherical particle near a rough bed, a measuring instrument was devised by making use of strain gauges and a dynamic strain-meter. The measurements of drag force were conducted under various conditions where the relative exposure of a particle to the flow and the constitution of surrounding particles were changed. These effects on drag force acting upon a particle near a bed were clarified experimentally. Not only the average magnitude of drag force but also the statistical properties of its fluctuation were investigated. The results obtained by these measurements and their analyses must be made available for the research study of mechanics of bed load transport.