Title :

Capillary-driven horseshoe vortex forming around a micro-pillar

Author(s) :

Ozawa, K. [Auteur]
Tokyo University of Science [Tokyo]
Nakamura, H. [Auteur]
Tokyo University of Science [Tokyo]
University of Arkansas [Fayetteville]
Shimamura, K. [Auteur]
Tokyo University of Science [Tokyo]
Dietze, G.F. [Auteur]
Fluides, automatique, systèmes thermiques [FAST]
Yoshikawa, H.N. [Auteur]
Université Côte d'Azur [UniCA]
Zoueshtiagh, Farzam [Auteur]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Acoustique Impulsionnelle & Magnéto-Acoustique Non linéaire - Fluides, Interfaces Liquides & Micro-Systèmes - IEMN [AIMAN-FILMS - IEMN]
Kurose, K. [Auteur]
Tokyo University of Science [Tokyo]
Mu, L. [Auteur]
Dalian University of Technology
China University of Petroleum
Ueno, I. [Auteur correspondant]
Tokyo University of Science [Tokyo]

Journal title :

Journal of Colloid and Interface Science

Pages :

227-234

Publisher :

Elsevier

Publication date :

2023

ISSN :

0021-9797

English keyword(s) :

horseshoe vortex
wetting
meniscus
capillarity
micropilla

HAL domain(s) :

Physique [physics]/Mécanique [physics]/Mécanique des fluides [physics.class-ph]

English abstract : [en]

Hypothesis: Horseshoe vortices are known to emerge around large-scale obstacles, such as bridge pillars, due to an inertia-driven adverse pressure gradient forming on the upstream-side of the obstacle. We contend that a ...
Show more >Hypothesis: Horseshoe vortices are known to emerge around large-scale obstacles, such as bridge pillars, due to an inertia-driven adverse pressure gradient forming on the upstream-side of the obstacle. We contend that a similar flow structure can arise in thin-film Stokes flow around micro-obstacles, such as used in textured surfaces to improve wettability. This could be exploited to enhance mixing in microfluidic devices, typically limited to creeping-flow regimes.Experiments: Numerical simulations based on the Navier–Stokes equations are carried out to elucidate the flow structure associated with the wetting dynamics of a liquid film spreading around a 50 μm diameter micro-pillar. The employed multiphase solver, which is based on the volume of fluid method, accurately reproduces the wetting dynamics observed in current and previous (Mu et al., Langmuir, 2019) experiments.Findings: The flow structure within the liquid meniscus forming at the foot of the micro-pillar evinces a horseshoe vortex wrapping around the obstacle, notwithstanding that the Reynolds number in our system is extremely low. Here, the adverse pressure gradient driving flow reversal near the bounding wall is caused by capillarity instead of inertia. The horseshoe vortex is entangled with other vortical structures, leading to an intricate flow system with high-potential mixing capabilities.Show less >

Language :

Anglais

Popular science :

Non

ANR Project :

La Mécanique des Fluides au Service de la Sécurité Alimentaire

Collections :

• Institut d'Électronique, de Microélectronique et de Nanotechnologie (IEMN) - UMR 8520

Source :

Harvested from HAL