An Eulerian two-phase model for steady sheet flow using large-eddy simulation methodology
An Eulerian two-phase model for steady sheet flow using large-eddy simulation methodology
复制标题
使用大涡模拟方法的稳定片流的欧拉两相模型
DOI：
10.1016/j.advwatres.2017.11.016
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发表时间：
2018
影响因子：
4.7
通讯作者：
Chauchat, Julien
中科院分区：
文献类型：
--
作者：
Cheng, Zhen;Hsu, Tian-Jian;Chauchat, Julien
本文提出了一个适用于面流条件下的三维欧拉两相流泥沙输移模型。采用大涡模拟方法求解紊流和泥沙相互作用。具体而言，一个动态Smagorinsky封闭用于亚网格流体和沉积物应力，而亚网格的拖曳力的贡献包括使用漂移速度模型与类似的动态过程。泥沙应力的贡献，由于颗粒间的相互作用是由动力学理论的颗粒流在低到中等的泥沙浓度，而在高泥沙浓度的持久接触，颗粒压力和摩擦粘度的现象学封闭。该模型用单向稳定薄层流的全面高分辨率数据集进行验证（Revil-Baudard等人，2015，Journal of Fluid Mechanics，767，1-30）。在粒子Stokes数约为10时，模拟结果表明从流体速度分布获得的约化的von Kármán系数为κ = 0.215。流体湍流动能预算分析进一步表明，阻力引起的湍流耗散率是显着的片流层中，而在稀输运层中，压力功起着类似的作用，浮力耗散，这是典型的单相分层流配方中使用。本模型还再现了片层厚度和移动的床粗糙度类似的实测数据。然而，由此产生的移动的床粗糙度比经验公式预测的大两倍以上。进一步的分析表明，通过间歇性湍流运动的床面附近，分解的泥沙雷诺应力起着主要作用，在移动的床面粗糙度的增强。近床不稳定性分析还表明，湍流喷射运动与向上的泥沙悬浮通量高度相关，而湍流扫掠事件主要与向下的泥沙沉积通量相关。
A three-dimensional Eulerian two-phase flow model for sediment transport in sheet flow conditions is presented. To resolve turbulence and turbulence-sediment interactions, the large-eddy simulation approach is adopted. Specifically, a dynamic Smagorinsky closure is used for the subgrid fluid and sediment stresses, while the subgrid contribution to the drag force is included using a drift velocity model with a similar dynamic procedure. The contribution of sediment stresses due to intergranular interactions is modeled by the kinetic theory of granular flow at low to intermediate sediment concentration, while at high sediment concentration of enduring contact, a phenomenological closure for particle pressure and frictional viscosity is used. The model is validated with a comprehensive high-resolution dataset of unidirectional steady sheet flow (Revil-Baudard et al., 2015, Journal of Fluid Mechanics, 767, 1–30). At a particle Stokes number of about 10, simulation results indicate a reduced von Kármán coefficient ofκ≈ 0.215 obtained from the fluid velocity profile. A fluid turbulence kinetic energy budget analysis further indicates that the drag-induced turbulence dissipation rate is significant in the sheet flow layer, while in the dilute transport layer, the pressure work plays a similar role as the buoyancy dissipation, which is typically used in the single-phase stratified flow formulation. The present model also reproduces the sheet layer thickness and mobile bed roughness similar to measured data. However, the resulting mobile bed roughness is more than two times larger than that predicted by the empirical formulae. Further analysis suggests that through intermittent turbulent motions near the bed, the resolved sediment Reynolds stress plays a major role in the enhancement of mobile bed roughness. Our analysis on near-bed intermittency also suggests that the turbulent ejection motions are highly correlated with the upward sediment suspension flux, while the turbulent sweep events are mostly associated with the downward sediment deposition flux.
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影响因子：
--
作者：
T. Revil-Baudard;J. Chauchat
通讯作者：
T. Revil-Baudard;J. Chauchat
影响因子：
1.9
作者：
K T Kiger †;C. Pan §
通讯作者：
K T Kiger †;C. Pan §
DOI：
10.1098/rsta.2004.1427
发表时间：
2004-09
期刊：
Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences
影响因子：
--
作者：
J. Calantoni;K. Todd Holland;T. G. Drake
通讯作者：
J. Calantoni;K. Todd Holland;T. G. Drake
影响因子：
5.1
作者：
J. Chauchat;Zhen Cheng;T. Nagel;C. Bonamy;T. Hsu
通讯作者：
J. Chauchat;Zhen Cheng;T. Nagel;C. Bonamy;T. Hsu
影响因子：
--
作者：
J. Winterwerp
通讯作者：
J. Winterwerp