Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Civil Engineering


Sediment transport is one of the major problems confronting the hydraulic designer of today. Various aspects of sediment are encountered in the design of irrigation and drainage canals, the planning and design of reservoirs, the control of soil erosion, and the improvement and control of rivers and floodways. Due to the many variables encountered and the complex nature of the transport mechanics this problem has defied a completely satisfactory solution. Although a great deal of study has been devoted to sedimentation problems, there is much to be accomplished. Extensive investigation must be performed to increase the knowledge of the mechanics of sediment transport. It has been determined that, the vertical distribution, transportation, and deposition of sediment are related to the terminal fall velocity of the sediment particles themselves. However, the terminal fall velocity depends upon many variables, including type of fluid, type of flow, and variables of boundary geometry. The most important fluid variables are velocity distribution, vortex formation and shedding and turbulence. Shape, orientation, roundness, angularity, and roughness are important geometric variables. It also appears that the fall velocity of any individual particle is affected to some degree by the amount and type of other finer material in suspension. A. Purpose The purpose of this study was to determination the effect of various concentrations of film materials on the apparent resistance to motion of larger particles and in turn the relationship of this apparent resistance to the fall velocity of larger particles. B. Scope The scope of this study was limited to the investigation of the fall velocity of spheres falling singularly in varying concentrations of bentonite clay and water. The spheres used were of two types, glass and steal. The variation in density of the spheres permitted study of the fall velocity over a wide range of concentrations. The denser sphere had to be used at higher concentrations in order to produce resultant frag force of sufficient magnitude to be picked up by the instrument used. Bentonite was chosen because it was commercially available in large quantities, and is typical of much of the fine material found in streams.

Library of Congress Subject Headings

Fluid dynamics
Frictional resistance (Hydrodynamics)




South Dakota State University