@article{93a9774323d449e68d75e19ed6570758,
title = "Controlling capillary fingering using pore size gradients in disordered media",
abstract = "Capillary fingering is a displacement process that can occur when a nonwetting fluid displaces a wetting fluid from a homogeneous disordered porous medium. Here, we investigate how this process is influenced by a pore size gradient. Using microfluidic experiments and computational pore-network models, we show that the nonwetting fluid displacement behavior depends sensitively on the direction and the magnitude of the gradient. The fluid displacement depends on the competition between a pore size gradient and pore-scale disorder; indeed, a sufficiently large gradient can completely suppress capillary fingering. By analyzing capillary forces at the pore scale, we identify a nondimensional parameter that describes the physics underlying these diverse flow behaviors. Our results thus expand the understanding of flow in complex porous media and suggest a new way to control flow behavior via the introduction of pore size gradients.",
author = "Lu, {Nancy B.} and Browne, {Christopher A.} and Amchin, {Daniel B.} and Nunes, {Janine K.} and Datta, {Sujit S.}",
note = "Funding Information: It is a pleasure to acknowledge N. Bizmark and H. J. Cho for helpful feedback on the manuscript and R. K. Prud'homme and H. A. Stone for stimulating discussions. We acknowledge use of the Princeton Institute for the Science and Technology of Materials (PRISM) clean room and the Princeton Institute for Computational Science and Engineering for computer cluster access. This work was supported by startup funds through Princeton University. N.B.L. was supported in part by the Mary and Randall Hack Graduate Award of the Princeton Environmental Institute. This material is also based upon work supported by the National Science Foundation Graduate Research Fellowship Program (to C.A.B.) under Grant No. DGE-1656466. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. Publisher Copyright: {\textcopyright} 2019 American Physical Society.",
year = "2019",
month = aug,
day = "21",
doi = "10.1103/PhysRevFluids.4.084303",
language = "English (US)",
volume = "4",
journal = "Physical Review Fluids",
issn = "2469-990X",
publisher = "American Physical Society",
number = "8",
}