AI 中文总结
研究不同几何形状受限微通道中微滚子的动力学，结合实验、模拟和标度分析，发现收缩通道中微滚子速度变化规律，开发标度框架，揭示远场旋转流和近场剪切流对微滚子动力学的不同作用，为控制其动力学提供指导。
AI 中文摘要
旋转粒子靠近表面时可平移，形成具有广泛生物医学和微流体应用的微滚子。本文通过结合实验、数值模拟和标度分析，研究了不同几何形状受限微通道中微滚子的动力学。在收缩通道中，微滚子靠近收缩区域时平移速度降低。在矩形和圆柱形通道中，随着特征通道宽度减小会发生速度反转。利用自由平移的无力条件，开发了一个可推广到不同通道几何形状的系统标度框架。标度分析得出平移速度与受限程度的函数依赖关系，与实验和模拟结果吻合良好。重要的是，证明了远场旋转流产生的粘性应力控制观察到的速度降低和反转，而近场剪切流产生的平移阻力在紧密限定时抑制平移。分析揭示的这些流动分量的不同作用可为控制受限流体环境中微滚子动力学提供实际指导。
英文摘要
Rotating particles can translate when placed near a surface, forming microrollers with a wide range of biomedical and microfluidic applications. In this work, we investigate the dynamics of microrollers in confined microchannels with different geometries by combining experiments, numerical simulations, and scaling analysis. In constricted channels, we find that the translational velocity of a microroller decreases as it approaches the constricted region. In both rectangular and cylindrical channels, velocity reversal occurs as the characteristic channel width decreases. Using the force-free condition for free translation, we develop a systematic scaling framework that can be generalized to different channel geometries. The scaling analysis yields functional dependences of the translational velocity on the degree of confinement, which agree well with both experiments and simulations. Importantly, we demonstrate that the viscous stress generated by the far-field rotlet flow governs the observed velocity reduction and reversal, while the translational resistance resulting from the near-field shear flow suppresses translation under tight confinement. The distinct roles of these flow components revealed by our analysis may provide practical guidance for controlling microroller dynamics in confined fluid environments.
