2025-09-22 大阪大学
＜関連情報＞
- https://www.entrance.es.osaka-u.ac.jp/features-news/2539/
- https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/experimental-and-numerical-study-on-the-inertial-migration-of-hydrogel-particles-suspended-in-square-channel-flows/BFA310D3F0454327B5E0595F2E2225C8
正方形流路内を懸濁するハイドロゲル粒子の慣性移動に関する実験的・数値的研究 Experimental and numerical study on the inertial migration of hydrogel particles suspended in square channel flows
Yuma Hirohata,Kazusa Sai,Yuki Tange,Tomohiro Nishiyama,Haruka Minato,Daisuke Suzuki,Tomoaki Itano,Kazuyasu Sugiyama and Masako Sugihara-Seki
Journal of Fluid Mechanics Published:18 September 2025
DOI:https://doi.org/10.1017/jfm.2025.10574
Abstract
The inertial migration of hydrogel particles suspended in a Newtonian fluid flowing through a square channel is studied both experimentally and numerically. Experimental results demonstrate significant differences in the focusing positions of the deformable and rigid particles, highlighting the role of particle deformability in inertial migration. At low Reynolds numbers (Re), hydrogel particles migrate towards the centre of the channel cross-section, whereas the rigid spheres exhibit negligible lateral motion. At finite Re, they focus at four points along the diagonals in the downstream cross-section, in contrast to the rigid particles which focus near the centre of the channel face at similar Re. Numerical simulations using viscous hyperelastic particles as a model for hydrogel particles reproduced the experimental results for the particle distribution with an appropriate Young’s modulus of the hyperelastic particles. Further numerical simulations over a broader range of Re and the capillary number (Ca) reveal various focusing patterns of the particles in the channel cross-section. The phase transitions between them are discussed in terms of the inertial lift and the lift due to particle deformation, which would act in the direction towards lower shear. The stability of the channel centre is analysed using an asymptotic expansion approach to the migration force at low Re and Ca. The theoretical analysis predicts the critical condition for the transition, which is consistent with the direct numerical simulation. These experimental, numerical and theoretical results contribute to a deeper understanding of inertial migration of deformable particles.
