Granular-fluid avalanches: the role of vertical structure and velocity shear
Granular-fluid avalanches: the role of vertical structure and velocity shear
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颗粒流体雪崩：垂直结构和速度剪切的作用
DOI：
10.1017/jfm.2023.1023
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发表时间：
2024
影响因子：
3.7
通讯作者：
Meng X
中科院分区：
文献类型：
--
作者：
Meng X
对泥石流的实地观测常常表明，在一个深干的粒状锋面之后，是一个逐渐变薄、含水越来越多的尾部。这些特征已经在最近的实验室水槽实验中被捕获(Taylor-Noonan et al.， J. Geophys。Res.：地球冲浪。， vol. 127, 2022, e2022JF006622)。在这些实验中，使用不同的初始释放体积来研究不饱和单分散谷物-水混合物在下坡流向水平流动垫时的动力学。在相同颗粒释放体积下，还研究了相应的干颗粒流动，以显示间隙流体的影响。含有水的泥石流比同等体积的干颗粒更具流动性。在湿气流中，干锋的形成主要取决于气流的非均匀垂直结构和速度切变。b孟等人的深度平均理论包含了这些影响。， vol. 943, 2022, A19)，本文使用高分辨率激波捕获方案定量模拟干湿实验流。结果表明，速度切变使位于自由面附近的干颗粒向前移动，形成干锋。相对于后面含水较多的物质，前缘的运动阻力更大，这与假定塞子流并只形成小干嘴的泥石流模型相比，减少了计算出的总跑出距离。速度剪切也意味着有水的净输送到流的后部。这就产生了一个薄的过饱和尾巴，与实验观察一致，它对翻滚波不稳定。
Field observations of debris flows often show that a deep dry granular front is followed by a progressively thinner and increasingly watery tail. These features have been captured in recent laboratory flume experiments (Taylor-Noonan et al., J. Geophys. Res.: Earth Surf., vol. 127, 2022, e2022JF006622). In these experiments different initial release volumes were used to investigate the dynamics of an undersaturated monodisperse grain–water mixture as it flowed downslope onto a horizontal run-out pad. Corresponding dry granular flows, with the same particle release volumes, were also studied to show the effect of the interstitial fluid. The inclusion of water makes debris flows much more mobile than equivalent volumes of dry grains. In the wet flows, the formation of a dry front is crucially dependent on the heterogeneous vertical structure of the flow and the velocity shear. These effects are included in the depth-averaged theory of Meng et al. (J. Fluid Mech., vol. 943, 2022, A19), which is used in this paper to quantitatively simulate both the wet and dry experimental flows using a high-resolution shock-capturing scheme. The results show that velocity shear causes dry grains (located near the free surface) to migrate forwards to create a dry front. The front is more resistant to motion than the more watery material behind, which reduces the overall computed run-out distance compared with debris-flow models that assume plug flow and develop only small dry snouts. Velocity shear also implies that there is a net transport of water to the back of the flow. This creates a thin oversaturated tail that is unstable to roll waves in agreement with experimental observations.
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影响因子：
3.7
作者：
F. Bouchut;E. Fernández-Nieto;A. Mangeney;G. Narbona-Reina
通讯作者：
F. Bouchut;E. Fernández-Nieto;A. Mangeney;G. Narbona-Reina
平滑二维凹凸上颗粒流的多种解决方案
影响因子：
3.7
作者：
S. Viroulet;J. Baker;A. Edwards;C. Johnson;C. Gjaltema;P. Clavel;J. Gray
通讯作者：
J. Gray
DOI：
10.1029/2022jf006893
发表时间：
2023-04
期刊：
Journal of Geophysical Research: Earth Surface
影响因子：
--
作者：
W. Sun;X. Meng;Y. Wang;S. Hsiau;Z. You
通讯作者：
W. Sun;X. Meng;Y. Wang;S. Hsiau;Z. You
影响因子：
3.7
作者：
J. L. Baker;C. G. Johnson;J. Gray
通讯作者：
J. L. Baker;C. G. Johnson;J. Gray
影响因子：
--
作者：
S. Pudasaini
通讯作者：
S. Pudasaini