微游泳者在泊肃叶流中的趋流性

中文摘要 AI 辅助

我们利用解析计算和数值模拟研究了球形微游泳者在平面泊肃叶流中的运动。结果表明，微游泳者的取向发生周期性振荡，其动力学类似于单摆。振荡周期与通道宽度及在最大取向角处评估的第一类完全椭圆积分成正比，与最大流速和自推进速度乘积的平方根成反比。基于一个振荡周期内沿流动方向的净位移以及最大和最小速度的符号，我们识别出五种运动状态：上游运动、振荡上游运动、零漂移振荡运动、振荡下游运动和下游运动。净位移由自推进速度与最大流速之比以及第一类和第二类完全椭圆积分共同决定。最大和最小速度的符号由速度比和取向角的余弦决定。流动非均匀性促进上游迁移，而惯性升力在一个振荡周期内产生的径向位移可忽略不计。这些发现确定了控制球形微游泳者运动的关键参数，并为理解微生物运动性和设计具有预定运动状态的微型机器人提供了重要意义。

英文摘要

We investigate the motion of a spherical microswimmer in a planar Poiseuille flow using analytical calculations and numerical simulations. Our results show that the microswimmer's orientation undergoes periodic oscillations governed by pendulum-like dynamics. The oscillation period is proportional to the channel width and to the complete elliptic integral of the first kind evaluated at the maximum orientation angle, and inversely proportional to the square root of the product of the maximum flow speed and the self-propulsion speed. Based on the net displacement along the flow direction within one oscillation period and the signs of the maximum and minimum velocities, we identify five motion states: upstream, oscillatory upstream, zero-drift oscillatory, oscillatory downstream, and downstream motion. The net displacement is jointly determined by the ratio of the self-propulsion speed to the maximum flow speed and the complete elliptic integrals of the first and second kinds. The signs of the maximum and minimum velocities are determined by the speed ratio and the cosine of the orientation angle. Flow nonuniformity promotes upstream migration, whereas inertial lift produces negligible radial displacement during one oscillation period. These findings identify the key parameters governing the motion of spherical microswimmers and provide significant implications for understanding microorganism motility and designing microrobots with prescribed motion states.

发表机构

• Ningxia University（宁夏大学）
• University of Chinese Academy of Sciences (UCAS)（中国科学院大学）

机构由 AI 辅助整理，请以论文原文为准。