Entrainment of single particles in a turbulent open-channel flow: a numerical study
Entrainment of single particles in a turbulent open-channel flow: a numerical study
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DOI：
10.1080/00221686.2016.1140683
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发表时间：
2016-03
影响因子：
2.3
通讯作者：
B. Vowinckel;R. Jain;Tobias Kempe;J. Fröhlich
中科院分区：
文献类型：
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作者：
B. Vowinckel;R. Jain;Tobias Kempe;J. Fröhlich
摘要本文研究了含单分散球形颗粒的明渠湍流中的侵蚀事件。数据是在先前的研究中使用相位分辨浸入边界法直接数值模拟得到的。颗粒的迁移率低于其初始运动的标称阈值，并沉降到由相同大小的六边形球体堆积层组成的粗糙床上。条件平均用于提取侵蚀事件的特征特征，为检测和考虑可能的流动结构不对称定义了合适的准则。高分辨率的数据集提供了对侵蚀关键机制的详细见解。结果表明，粒子碰撞以及随后在几个体积单位的时间尺度上的横扫事件是造成侵蚀的原因。
ABSTRACT This paper investigates erosion events in a turbulent open channel flow laden with monodisperse spherical particles. The data were generated in a previous study using direct numerical simulations with a phase-resolving immersed boundary method. The particles have a mobility below their nominal threshold of incipient motion and settle onto the rough bed that consists of a hexagonally packed layer of spheres with the same size. Conditioned averaging is employed to extract the characteristic features of an erosion event, defining a suitable criterion for detection and accounting for possible asymmetry of flow structures. The highly resolved dataset provides detailed insight into the key-mechanisms of erosion. The results show that a particle collision, together with a subsequent sweep event on time scales of several bulk units, is responsible for the erosion.