Numerical simulation for sediment transport in sheetflow regime using DEM-MPS
Numerical simulation for sediment transport in sheetflow regime using DEM-MPS
复制标题
使用 DEM-MPS 进行片流流态中泥沙输运的数值模拟
DOI：
10.1007/978-981-15-0291-0_64
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Hitoshi Gotoh
中科院分区：
文献类型：
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作者：
Eiji Harada;Hiroyuki Ikari;Yuma Shimizu;Hitoshi Gotoh
在海岸带周围观测到的高度集中的泥沙输运或片流，对海岸过程有重要影响。然而，由于片状流是具有高度集中的快速颗粒流的现象，因此难以从实验测量直接测量片状流的内部结构。同时，由于薄层流是一种强非线性多相流现象，对其进行数值模拟仍然是一个具有挑战性的问题。本文在前人试验研究的基础上，对均匀流条件下的面流泥沙输移过程进行了数值模拟，作为了解面波带面流机理的一种途径。在本数值模型中，为了高精度地模拟有自由面明渠水流下的薄层流，液相采用了拉格朗日模型中的增强移动粒子半隐式（MPS）方法。另一方面，离散元法（DEM）被应用到固体颗粒相跟踪单个颗粒的运动。通过耦合这些方法，三维拉格朗日-拉格朗日耦合模型准备的计算调查的片状流层的内部结构的目的。从数值模拟结果来看，在高含沙浓度的薄层水流中，颗粒间的碰撞频率较高，同时从泥沙输移计算的角度来看，颗粒间的碰撞力是揭示薄层水流中泥沙输移机理的关键因素。
A regime of highly concentrated sediment transport, or sheetflow, which is observed around coastal surf-zone, has significant impact on a coastal process. However, it is difficult to directly measure an inner-structure of the sheetflow from experimental measurement, because the sheetflow is a phenomenon with highly concentrated fast granular flows. As well as, because the sheetflow is a phenomenon in strong non-linear multi-phase flow, an implementation of numerical simulation is still a challenging problem. In the present research, as one way to the understanding of surf-zone sheetflow mechanism, the numerical simulation for the sheetflow sediment transport is performed in the uniform flow condition, by reference to the previous experimental results. In the present numerical model, to simulate sheetflow under open channel flow with free surface with a high degree of accuracy, the enhanced Moving Particle Semi-implicit (MPS) method, which is one of the Lagrangian models, is used to the liquid phase. On the other hand, the Distinct Element Method (DEM) is applied to the solid-particle phase to track individual particle motion. By coupling these methods, the three-dimensional Lagrange-Lagrange coupling model is prepared for the purpose of computational investigation of an inner structure of the sheetflow layer. From the present numerical results, the significant collision frequency between particles is found in the sheetflow layer including a high sediment concentration, concurrently, simulation result indicates inter-particle force by particle collision is the key factor to reveal the sediment transport mechanism in the sheetflow layer, from the viewpoint of computational sediment transport.