Related Experiment Video
Updated: Nov 15, 2025
11:51
Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
Published on: February 22, 2018
8.9K
Inertial Migration of Neutrally Buoyant Spherical Particles in Square Channels at Moderate and High Reynolds Numbers
Yanfeng Gao1,2, Pascale Magaud2, Lucien Baldas2
1College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China.
Micromachines
|March 6, 2021
Summary
Particle migration in microchannels is key. New equilibrium positions emerge at higher Reynolds numbers (Re), optimizing particle focusing and ordering in narrow square channels.
Area of Science:
- Fluid Dynamics
- Microfluidics
- Particle Migration
Background:
- Inertial migration of particles in microchannels is well-studied, but focusing and ordering remain unclear in small square channels at high Reynolds numbers (>200).
- Understanding particle behavior in microchannels is crucial for applications like cell sorting and particle manipulation.
Purpose of the Study:
- To investigate particle inertial migration and focusing in square microchannels (<100 µm) across a wide range of Reynolds numbers (Re: 5–280).
- To analyze the emergence of new equilibrium positions and the longitudinal ordering of particles under varying flow conditions.
Main Methods:
- In situ visualization of particle flow within square microchannels.
- Analysis of particle migration behaviors at Reynolds numbers from 5 to 280.
- Characterization of particle equilibrium positions and longitudinal ordering.
Main Results:
- New equilibrium positions for particles appear above a critical Reynolds number, influenced by particle size ratio and volume fraction.
- An optimal Reynolds number was identified for maximizing the proportion of particles at equilibrium positions.
- The longitudinal ordering process, forming particle trains, was analyzed across different flow conditions.
Conclusions:
- Particle migration in square microchannels exhibits complex behavior at high Reynolds numbers, with new equilibrium positions forming.
- Optimal flow conditions exist for maximizing particle focusing and ordering, crucial for microfluidic device design.
- This study clarifies particle dynamics in small square microchannels, advancing microfluidic particle manipulation.
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