Loose Boundary Hydraulics

Sediment transport, two-phase flow, loose boundary hydraulics are some of the names used to identify problems of interaction between fluid flow (water or air) and its boundaries that may be non-cohesive (alluvial) or cohesive. Unlike in the classical hydraulics the boundaries can change their geometry and roughness with changing flow conditions. Some of the material from the boundaries may be entrained into the flow, or sediment may be added to the flow, such as by tributaries, as suspended matter. Since the changing boundaries are the central feature of most flow processes in nature, the term loose boundary hydraulics is used here. A special case is the transport of granular material in pipelines.