TY - JOUR
T1 - Particle trapping in merging flow junctions by fluid-solute-colloid-boundary interactions
AU - Shin, Sangwoo
AU - Ault, Jesse T.
AU - Toda-Peters, Kazumi
AU - Shen, Amy Q.
N1 - Funding Information:
We thank Bhargav Rallabandi for helpful discussions. S.S. acknowledges support from the National Science Foundation under Grant No. CBET-1930691. K.T. and A.Q.S. thank Okinawa Institute of Science and Technology Graduate University (OIST) for their financial support, with subsidy funding from the Cabinet Office, Government of Japan. A.Q.S. also acknowledges financial support from JSPS under Grant 18H01135.
Publisher Copyright:
© 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
PY - 2020/2/27
Y1 - 2020/2/27
N2 - Merging of different streams in channel junctions represents a common mixing process that occurs in systems ranging from soda fountains and bathtub faucets to chemical plants and microfluidic devices. Here, we report a spontaneous trapping of colloidal particles in a merging flow junction when the merging streams have a salinity contrast. We show that the particle trapping is a consequence of nonequilibrium interactions between the particles, solutes, channel, and the freestream flow. A delicate balance of transport processes results in a stable near-wall vortex that traps the particles. We use three-dimensional particle visualization and numerical simulations to provide a rigorous understanding of the observed phenomenon. Such a trapping mechanism is unique from the well-known inertial trapping enabled by vortex breakdown [Proc. Natl. Acad. Sci. USA 111, 4770 (2014)PNASA60027-842410.1073/pnas.1321585111], or the solute-mediated trapping enabled by diffusiophoresis [Phys. Rev. X 7, 041038 (2017)2160-330810.1103/PhysRevX.7.041038], as the current trapping is facilitated by both the solute and the inertial effects, suggesting a new mechanism for particle trapping in flow networks.
AB - Merging of different streams in channel junctions represents a common mixing process that occurs in systems ranging from soda fountains and bathtub faucets to chemical plants and microfluidic devices. Here, we report a spontaneous trapping of colloidal particles in a merging flow junction when the merging streams have a salinity contrast. We show that the particle trapping is a consequence of nonequilibrium interactions between the particles, solutes, channel, and the freestream flow. A delicate balance of transport processes results in a stable near-wall vortex that traps the particles. We use three-dimensional particle visualization and numerical simulations to provide a rigorous understanding of the observed phenomenon. Such a trapping mechanism is unique from the well-known inertial trapping enabled by vortex breakdown [Proc. Natl. Acad. Sci. USA 111, 4770 (2014)PNASA60027-842410.1073/pnas.1321585111], or the solute-mediated trapping enabled by diffusiophoresis [Phys. Rev. X 7, 041038 (2017)2160-330810.1103/PhysRevX.7.041038], as the current trapping is facilitated by both the solute and the inertial effects, suggesting a new mechanism for particle trapping in flow networks.
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U2 - 10.1103/PhysRevFluids.5.024304
DO - 10.1103/PhysRevFluids.5.024304
M3 - Article
AN - SCOPUS:85080873739
SN - 2469-990X
VL - 5
JO - Physical Review Fluids
JF - Physical Review Fluids
IS - 2
M1 - 024304
ER -