假冬冬, 陈长英, 张幸农, 应强. 典型窝崩三维数值模拟[J]. 水科学进展, 2020, 31(3): 385-393. DOI: 10.14042/j.cnki.32.1309.2020.03.008
引用本文: 假冬冬, 陈长英, 张幸农, 应强. 典型窝崩三维数值模拟[J]. 水科学进展, 2020, 31(3): 385-393. DOI: 10.14042/j.cnki.32.1309.2020.03.008
JIA Dongdong, CHEN Changying, ZHANG Xingnong, YING Qiang. 3-D numerical simulation of the Ω caving in riverbanks[J]. Advances in Water Science, 2020, 31(3): 385-393. DOI: 10.14042/j.cnki.32.1309.2020.03.008
Citation: JIA Dongdong, CHEN Changying, ZHANG Xingnong, YING Qiang. 3-D numerical simulation of the Ω caving in riverbanks[J]. Advances in Water Science, 2020, 31(3): 385-393. DOI: 10.14042/j.cnki.32.1309.2020.03.008

典型窝崩三维数值模拟

3-D numerical simulation of the Ω caving in riverbanks

  • 摘要: 窝崩是冲积河流常见的一种崩岸类型,具有发展速度快、破坏力强等特点,且不易成功模拟。以长江下游扬中河段指南村窝崩为例,基于窝崩机理及其力学模式,采用考虑回流区紊动影响的挟沙力公式模拟窝塘内泥沙输移,初步建立了窝崩三维数值模拟方法。研究结果表明:窝崩发生初期窝塘内局部水流具有底层流速大于上层流速的特征,这为窝塘底部及坡脚淘刷提供了动力条件;窝塘内回流区水流挟沙力的计算对窝崩形态模拟结果存在显著影响,考虑回流区紊动影响的泥沙输移特性后,模拟结果与实测结果基本吻合,可较好地模拟窝崩的快速发展过程。研究成果可为窝崩机理的深入认识和窝崩治理提供科技支撑。

     

    Abstract: The Ω caving in riverbanks is one of the typical bank erosion patterns occurred in alluvial rivers which develops quickly and increases the instability of dikes. The numerical simulation of this type of bank erosion is still a challenging task. The Zhinancun bank caving developed at the lower Yangtze River was investigated in this paper, and a 3-D numerical method for modeling the Ω caving in the riverbank was proposed based on the mechanism of bank erosion. The sediment transport capacity in the circumfluence zone was calculated by considering the influences of turbulence intensity. The simulated results indicated that the velocity close to the riverbed is larger than that in the upper layers in the circumfluence zone during the processes of riverbank collapse, which becomes the driving factors for the riverbed scouring and thus bank erosion. The determination of the sediment transport capacity has a great influence on the simulated shape of the bank which can be more accurately simulated by considering the effect of turbulence intensity. This study could improve our understanding of the mechanism of riverbank collapse.

     

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