On related aspects in modeling of hydrodynamic and sediment transport processes in muddy estuaries
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摘要: 为研究淤泥质河口的水沙运动规律,建立了用于模拟淤泥质河口水沙运动的二维数学模型。该模型采用基于无结构三角网格下的有限体积法对方程组进行离散,结合Roe-MUSCL方法及时间方向的预测-校正格式,使模型在时空方向具有二阶计算精度。模型中分别采用不同方法计算粘性和非粘性泥沙的输移源项,并引入粘性泥沙的起动流速和冲刷率计算公式。采用已有的概化水槽试验数据对模型进行了初步验证。然后模拟了1995年10月小潮及大潮期间海河口的潮流运动与泥沙输移过程,计算得到的潮位、潮流速及含沙量过程与实测过程符合较好,结果表明模型能够用来模拟淤泥质河口粘性和非粘性泥沙的不平衡输移过程。同时还比较了泥沙输移源项的不同处理方式对计算结果的影响,计算表明在淤泥质河口水沙运动数学模型中必须同时考虑粘性和非粘性泥沙的输移。Abstract: A two-dimensional numerical model is presented, which employs a finite volume method based on an unstructured triangular mesh, and uses the Roe-MUSCL scheme and the predictor-corrector procedure for time stepping.In the model, the source terms for the transport of cohesive and non-cohesive sediments are respectively calculated by different methods.Besides, the formulae of incipient velocity and erosion source term for cohesive sediments are both applied.The model is first validated against the available observed data obtained from a flume experiment.It is then applied to simulate the processes of hydrodynamic and sediment transport in the Haihe Estuary.The model predictions generally agreed with the observed data measured during the neap and spring tidal cycles in September 1995, which demonstrates the capability of the model to simulating the transport process of both cohesive and non-cohesive sediment in muddy estuaries. The use of different sediment transport treatments on model simulations is further investigated.The result shows that it is necessary to consider the transport of both cohesive and non-cohesive sediments in muddy estuaries.
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Keywords:
- muddy estuary /
- 2-D numerical model /
- finite volume method /
- sediment transport /
- cohesive sediment
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