Impact of Dike Structures on Sediment Transport in the Alluvial Rivers.

摘要

The objective is to study turbulent flow and sediment transport near dike structures of various geometries through an integrated laboratory experimental, numerical modeling, and field application. Major accomplishment includes: (1) developed a two-dimensional depth-averaged hydrodynamic model to simulate the evolution of meandering channels from the complex interaction between downstream and secondary flows, bed load and suspended sediment transport, and bank erosion. The model correctly replicates the different phases of the evolution of free meandering channels in experimental laboratory settings, such as downstream and upstream migration, lateral extension, and rotation of meander bends; (2) developed a three-dimensional model and simulated flow field around the experimental dikes. Experimental data from the laboratory study of flow in a flat bed and scoured bed around a series of three dikes were used to verify the results from the numerical model; (3) evaluated 31 commonly used formulae for predicting the total sediment load. This study attributed these deviations to the stochastic properties of bed shear stresses due to varying flow field and sediment sizes. Seven papers have been submitted to peer-reviewed journals, among them, four have been published. One Ph.D. and one MS degree are awarded to graduate students, and four high-school students are trained as summer interns.