Numerical study on the motion characteristics of an elastic fiber migrating in a cylindrical Couette flow with centrifugal effect
Numerical study on the motion characteristics of an elastic fiber migrating in a cylindrical Couette flow with centrifugal effect
复制标题
DOI：
10.1007/s10409-022-22423-x
复制
发表时间：
2023-03-01
影响因子：
3.5
通讯作者：
Cui，Jingyu
中科院分区：
文献类型：
--
作者：
Jin，Yuzhen;Liu，Yibo;Cui，Jingyu
本研究以数值方式探讨弹性纤维在具有固定内柱的圆柱Couette流中迁移的运动特性。流体-纤维相互作用的解决浸没边界格子玻尔兹曼方法（IB-LBM）。结果表明，纤维在离心力作用下发生径向迁移。在径向迁移过程中，柔顺纤维将首先经历不可重复的翻滚运动，然后是平移运动，直到它们到达外圆筒。不经历任何翻滚的纤维将需要更长的迁移时间。因此，纤维的翻滚有助于加速其径向迁移过程。发现将纤维放置得太靠近外圆筒或减小纤维的柔性（Λ*）抑制其翻滚运动。增加纤维的线密度（ρs*）不会改变其轨道类别，但会降低纤维在翻滚阶段的径向迁移速度，从而导致径向迁移效率降低。对于不引起纤维翻滚的Λ* 值，Λ* 值的增加降低了迁移效率。然而，当Λ* 增加到临界值时，发生翻滚运动，并且迁移效率随着Λ* 值的增加而增加。研究结果丰富了我们对离心剪切流中纤维迁移特性的认识。
This study numerically explores the motion characteristics of an elastic fiber migrating in a cylindrical Couette flow with a fixed inner cylinder. The fluid-fiber interaction is resolved by the immersed boundary-lattice Boltzmann method (IB-LBM). The results show that the fiber experiences centrifugal movements with an obvious radial migration tendency. During the radial migration process, compliant fibers will first experience a non-repeatable tumbling motion, followed by a translation motion until they reach the outer cylinder. Fibers that do not experience any tumbling will need a longer migration time. Therefore, the tumbling of fiber helps to accelerate its radial migration process. Placing the fiber too closer to the outer cylinder or decreasing the flexibility of the fiber (Λ*) is found to suppress its tumbling motion. Increasing the linear density of the fiber (ρs*) would not change its orbit class, but it would decrease the radial migration speed of the fiber in its tumbling stage, and thus leads to a lower radial migration efficiency. ForΛ* values that cause no fiber tumbling, an increase inΛ* value decreases the migration efficiency. However, asΛ* increases to a critical value, tumbling motion occurs, and the migration efficiency increases as theΛ* value increases. The results may enrich our understanding of fiber migration characteristics in shear flows where the centrifugal effect is involved.