ABSTRACT
Sediment transport, two-phase flow, loose boundary hydraulics are some of the names used to identify the interaction between a fluid flow and a granular material. The granular material forms some or all the boundaries of the flow and may be mixed into the flow. Except conveyance in pipelines where the boundaries are usually formed by the pipe, the flow boundaries change in form and roughness with flow conditions. The crucial feature is interaction between fluid and sediment, that is, sediment transport cannot be treated in isolation from hydro or aerodynamics. These are subjects in their own right and have many unsolved problems, in particular in areas of turbulence, boundary layer, wave motion and diffusion, and all of these may be associated with transport of sediment. For convenience the sediments forming the boundaries of a flow are subdivided into cohesive and non-cohesive sediments, although there is a fairly broad transition range.
