Physical complexity to model morphological changes at a natural channel bend
Physical complexity to model morphological changes at a natural channel bend
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DOI：
10.1002/2015wr017917
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发表时间：
2016-08
影响因子：
5.4
通讯作者：
M. Guan;N. G. Wright;P. Sleigh;S. Ahilan;R. Lamb
中科院分区：
文献类型：
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作者：
M. Guan;N. G. Wright;P. Sleigh;S. Ahilan;R. Lamb
本研究开发了一个二维（2-D）深度平均模型，通过包括二次流校正，用于自然弯道处的形态变化。该模型在两个实验室规模的事件中进行了测试。现场研究进一步采用，以证明该模型的能力，在预测床的变形在自然弯曲。此外，还测试了一系列具有不同沉积物相关参数设置的情景，以探索二维模型模拟自然弯曲处形态变化的可能性，并研究可靠建模所需的物理复杂性。结果表明，二维深度平均模型可以合理地重建弯曲处的水动力和形态特征，前提是该模型解决了二次流校正，并以实用的方式合理地参数化通道内的颗粒尺寸。输沙公式、糙率等因素对弯曲河床变化规律的影响相对较小。研究表明，在使用二维模型模拟天然弯曲处的河床变形时，应优先考虑二次流效应和粒度参数化。
This study developed a two‐dimensional (2‐D) depth‐averaged model for morphological changes at natural bends by including a secondary flow correction. The model was tested in two laboratory‐scale events. A field study was further adopted to demonstrate the capability of the model in predicting bed deformation at natural bends. Further, a series of scenarios with different setups of sediment‐related parameters were tested to explore the possibility of a 2‐D model to simulate morphological changes at a natural bend, and to investigate how much physical complexity is needed for reliable modeling. The results suggest that a 2‐D depth‐averaged model can reconstruct the hydrodynamic and morphological features at a bend reasonably provided that the model addresses a secondary flow correction, and reasonably parameterize grain‐sizes within a channel in a pragmatic way. The factors, such as sediment transport formula and roughness height, have relatively less significance on the bed change pattern at a bend. The study reveals that the secondary flow effect and grain‐size parameterization should be given a first priority among other parameters when modeling bed deformation at a natural bend using a 2‐D model.