A two‐phase model for sheet flow regime based on dense granular flow rheology
A two‐phase model for sheet flow regime based on dense granular flow rheology
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DOI：
10.1029/2012jc008306
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发表时间：
2013-02
影响因子：
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通讯作者：
T. Revil-Baudard;J. Chauchat
中科院分区：
文献类型：
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作者：
T. Revil-Baudard;J. Chauchat
[1]本文提出了一个描述薄层水流泥沙输移的两相模型，其中颗粒间应力采用μ（I）流变学模型，紊流应力采用混合长度模型。在模型中，考虑了两个层：一个稀悬浮层和一个密集的泥沙床层。浓度分布由沉积床层中的双折射定律（I）和悬浮层中的劳斯分布获得。流速剖面，浓度剖面，和宏观参数（输沙率，厚度和粗糙度）与实验数据的比较显示出良好的一致性。这些比较表明，密集的颗粒流变学是相关的描述强烈的推移质输沙湍流制度（片流）。该模型较好地描述了从密相静止床到稀相悬浮床的过渡过程。此外，不同制度的致密颗粒流变学似乎能够捕获碰撞为主和顺从波动为主的片流之间的过渡，这取决于颗粒的特性。
[1] A two-phase model having a μ(I) rheology for the intergranular stresses and a mixing length approach for the turbulent stresses is proposed to describe the sheet flow regime of sediment transport. In the model, two layers are considered: a dilute suspension layer and a dense sediment bed layer. The concentration profile is obtained from the dilatancy law ϕ(I) in the sediment bed layer and from a Rouse profile in the suspension layer. The comparison of velocity profile, concentration profile, and macroscopic parameters (sediment transport rate, thickness, and roughness) with experimental data shows a good agreement. These comparisons demonstrate that the dense granular rheology is relevant to describe intense bed-load transport in turbulent regime (sheet flow). The transition from the dense static bed to the dilute suspension is well described by the present model. Also, the different regimes of the dense granular rheology seems to be able to capture the transition between collision-dominant and turbulent-fluctuations-dominant sheet flows, depending on the particle's characteristics.