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Updated: Oct 20, 2025

Analyzing Mixing Inhomogeneity in a Microfluidic Device by Microscale Schlieren Technique
Published on: June 12, 2015
Macroscopic and microscopic hydrodynamic mixing of stratified suspensions
Yasufumi Yamamoto1, Koki Yamada1, Yohsuke Tanaka2
1Department of Mechanical Engineering, Kansai University, 3-35 Yamate-cho 3-chome, Suita, Osaka 564-8680, Japan.
Abstract:
We conducted numerical experiments to investigate the mixing of stratified suspensions containing different types of particles. We used a point-force two-way coupling method. We studied the mixing behavior of stratified suspensions and we discovered two types of mixing: microscopic (individual-particle-level) and macroscopic (vessel-scale) collective mixing. In addition, we examined the vertical mixing speed of the stratified suspension. We used a simple theoretical model to analyze the fingering settling velocity. Then we introduced a nondimensional number representing the difference in collectivities of the upper and lower suspensions while accounting for particle terminal velocities. We discovered that the proposed nondimensional parameter has a negative sign that distinguishes the mixing form of only microscopic individual-particle-level mixing and a positive value that predicts the speed of macroscopic collective mixing of stratified suspensions.
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