Flow and bathymetry in sharp open‐channel bends: Experiments and predictions

作者：Jie Zeng, George S. Constantinescu, Koen Blanckaert, Larry Weber · 发表于：Water Resources Research · 年份：2008 · DOI：10.1029/2007wr006303 · 被引用次数：132 · 研究领域：Hydrology and Sediment Transport Processes、Soil erosion and sediment transport、Hydraulic flow and structures

This paper focuses on experiments and simulations conducted in very sharp open‐channel bends with flat and equilibrium bathymetry, corresponding to the initial and final phases of the erosion and deposition processes, respectively. The study of flow in curved open bends is relevant for flow in natural river configurations, as most river reaches are not straight. The configuration considered in the present work was designed as a test case in which the role of the cross‐sectional flow is more severe than in meandering natural river reaches (radius of curvature of the channel is close to the channel width) and, thus, can serve for validation of numerical models used to predict flow and sediment transport in river engineering applications. This paper presents detailed new experimental data on the equilibrium bathymetry as well as depth‐averaged distributions, vertical profiles, and cross‐sectional patterns of the streamwise velocity, the cross‐stream circulation, streamwise vorticity, and the turbulent kinetic energy at the initial and final stages of the erosion and deposition processes. The numerical simulations are performed using a three‐dimensional nonhydrostatic RANS model for flow, sediment transport, and bathymetry, which employs fine meshes, accounts for the effect of small bed forms, and avoids the use of the law of the wall. The model predicts, rather accurately, the distribution of the streamwise velocity, the cross‐stream circulation, and the turbulent kinetic energy...