Interface-resolved direct numerical simulation of the erosion of a sediment bed sheared by laminar channel flow
Interface-resolved direct numerical simulation of the erosion of a sediment bed sheared by laminar channel flow
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DOI：
10.1016/j.ijmultiphaseflow.2014.08.008
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发表时间：
2014-12-01
影响因子：
3.8
通讯作者：
Uhlmann, Markus
中科院分区：
文献类型：
--
作者：
Kidanemariam, Aman G.;Uhlmann, Markus
基于流固耦合的浸没边界技术和固固接触的软球方法的数值方法用于对水平面通道中球形颗粒厚床的流动引起的运动进行直接数值模拟。碰撞模型具有带有弹簧和阻尼器的法向力分量，以及受库仑摩擦定律限制的阻尼切向分量。在较宽的斯托克斯数范围内模拟单个粒子在粘性流体中与水平壁垂直碰撞的标准测试案例，产生与实验数据非常一致的有效恢复系数值。针对层流通道流的床载颗粒输送情况进行了模拟，涵盖了广泛的屏蔽数范围的 24 个不同参数值。当前结果与 Aussillous 等人实验的参考数据的比较。 (2013) 取得了很好的一致性。已证实，一旦超过已知阈值，颗粒流量将随屏蔽数的三次方变化。目前的数据表明，移动颗粒层的厚度（用透明流体区域的高度标准化）随着标准化流体流速的平方而增加。 (C) 2014 Elsevier Ltd. 保留所有权利。
A numerical method based upon the immersed boundary technique for the fluid-solid coupling and on a soft-sphere approach for solid-solid contact is used to perform direct numerical simulation of the flow-induced motion of a thick bed of spherical particles in a horizontal plane channel. The collision model features a normal force component with a spring and a damper, as well as a damping tangential component, limited by a Coulomb friction law. The standard test case of a single particle colliding perpendicularly with a horizontal wall in a viscous fluid is simulated over a broad range of Stokes numbers, yielding values of the effective restitution coefficient in close agreement with experimental data. The case of bed-load particle transport by laminar channel flow is simulated for 24 different parameter values covering a broad range of the Shields number. Comparison of the present results with reference data from the experiment of Aussillous et al. (2013) yields excellent agreement. It is confirmed that the particle flow rate varies with the third power of the Shields number once the known threshold value is exceeded. The present data suggests that the thickness of the mobile particle layer (normalized with the height of the clear fluid region) increases with the square of the normalized fluid flow rate. (C) 2014 Elsevier Ltd. All rights reserved.