The effect of heterogeneous roughness on conveyance capacity and application to the Shiono-Knight method

[摘要] Understanding the physical processes which occur within open-channel flow is necessary if the modelling of river flow is to be improved. This thesis examines in detail the flow in a type of channel which is common in natural rivers yet little researched, the heterogeneous channel (one whose bed is laterally horizontal but of varying roughness). The 3-D velocity field in a heterogeneous channel is mapped more fully and at a higher resolution than was achieved by the few previous studies of such channels, allowing the propagation and structure of turbulence within the channel to be investigated for the first time, using techniques such as Quadrant-Hole and Conditional Time Series analysis. Two bed configurations are examined - one of full-length strip roughness (with one half of the channel width rough and the other smooth) and the second of alternating rough and smooth sections in a “checkerboard” pattern. The former allows the investigation of fully-developed flow, while the latter is shown to more closely resemble the bed variation of a natural river. The thesis goes on to provide recommendations as to how the Shiono-Knight Method (SKM) should be applied to model a heterogeneous channel, bringing the research towards a real-world application.

[发布机构] University:University of Birmingham;Department:School of Engineering, Department of Civil Engineering

[关键词] T Technology;T Technology (General)