离心作用下柔性纤维在圆柱形Couette流中运动特性数值研究  

Numerical study on the motion characteristics of an elastic fiber migrating in a cylindrical Couette flow with centrifugal effect

作　　者：金玉珍 刘一伯 崔靖渝 Yuzhen Jin;Yibo Liu;Jingyu Cui(Key Laboratory of Fluid Transmission Technology of Zhejiang Province,Zhejiang Sci-Tech University,Hangzhou,310018,China;Key Laboratory of Modern Textile Machinery&Technology of Zhejiang Province,Zhejiang Sci-Tech University,Hangzhou,310018,China)

机构地区：[1]Key Laboratory of Fluid Transmission Technology of Zhejiang Province,Zhejiang Sci-Tech University,Hangzhou,310018,China [2]Key Laboratory of Modern Textile Machinery&Technology of Zhejiang Province,Zhejiang Sci-Tech University,Hangzhou,310018,China

出　　处：《Acta Mechanica Sinica》2023年第3期130-141,共12页力学学报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.51976200 and 12202393);the Science Foundation of Zhejiang Sci-Tech University(Grant No.22022018-Y).

摘　　要：本研究基于浸入边界-格子Boltzmann方法(IB-LBM)数值研究了柔性纤维在内圆柱固定的圆柱形Couette流中的运动特性.模拟结果表明,纤维在圆柱形Couette流中将会做离心运动,且运动过程中具有明显的径向迁移的趋势.在径向迁移过程中,柔性纤维首先会经历一次翻滚运动,然后进行平移运动直到其接触外圆柱.不经历任何翻滚运动的纤维将需要更长时间来完成这一迁移过程.因此纤维的翻滚运动有助于加速其径向迁移过程.将纤维放置的太靠近外圆柱或降低纤维的柔性(Λ^(*))将会抑制其翻滚运动.增加纤维的线密度(Λ^(*)s)不会改变纤维的迁移模式类别,但会降低纤维在翻滚阶段的径向迁移速度,从而降低整体径向迁移的效率.但Λ^(*)值较低时,纤维翻滚运动消失,此时增加Λ^(*)值会降低纤维的迁移效率.然而,当Λ^(*)值增加到一个临界值时,会引发纤维的翻滚运动,此时径向迁移的效率会随着Λ^(*)值的增加而增加.研究结果可以增进我们对离心作用下剪切流中纤维迁移特性的认知.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(ρ^(*)_(s))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.

关 键 词：Fiber dynamics Fluid-structure interaction Immersed boundary method Centrifugal effect Radial migration 

分 类 号：O3[理学—力学]