Particle segregation and dynamics in confined flows.

Nonlinearity in finite-Reynolds-number flow results in particle migration transverse to fluid streamlines, producing the well-known “tubular pinch effect” in cylindrical pipes. Here we investigate these nonlinear effects in highly confined systems where the particle size approaches the channel dimensions. Experimental and numerical results reveal distinctive dynamics, including complex scaling of lift forces with channel and particle geometry. The unique behavior described in this Letter has broad implications for confined particulate flows.

有限雷诺数流动中的非线性导致粒子横向于流体流线迁移，在圆柱管中产生众所周知的“管箍缩效应”。在此，我们研究在粒子尺寸接近通道尺寸的高度受限系统中的这些非线性效应。实验和数值结果揭示了独特的动力学，包括升力与通道和粒子几何形状的复杂比例关系。这篇快报中描述的独特行为对受限的颗粒流具有广泛的影响。