TY - JOUR
T1 - Stagnation points control chaotic fluctuations in viscoelastic porous media flow
AU - Haward, Simon J.
AU - Hopkins, Cameron C.
AU - Shen, Amy Q.
N1 - Funding Information:
ACKNOWLEDGMENTS. We acknowledge the support of the Okinawa Institute of Science and Technology (OIST) Graduate University with subsidy funding from the Cabinet Office, Government of Japan. We also acknowledge funding from Japan Society for the Promotion of Science (JSPS) Grants 20K14656 and 21K03884 and the Joint Research Projects supported by the JSPS and the Swiss National Science Foundation. We thank Mr. Kazumi Toda-Peters (OIST) for device fabrication and Dr. Stylianos Varchanis (OIST) for helpful discussions.
Publisher Copyright:
© 2021 National Academy of Sciences. All rights reserved.
PY - 2021/9/21
Y1 - 2021/9/21
N2 - Viscoelastic flows through porous media become unstable and chaotic beyond critical flow conditions, impacting widespread industrial and biological processes such as enhanced oil recovery and drug delivery. Understanding the influence of the pore structure or geometry on the onset of flow instability can lead to fundamental insights into these processes and, potentially, to their optimization. Recently, for viscoelastic flows through porous media modeled by arrays of microscopic posts, Walkama et al. [D. M. Walkama, N. Waisbord, J. S. Guasto, Phys. Rev. Lett. 124, 164501 (2020)] demonstrated that geometric disorder greatly suppressed the strength of the chaotic fluctuations that arose as the flow rate was increased. However, in that work, disorder was only applied to one originally ordered configuration of posts. Here, we demonstrate experimentally that, given a slightly modified ordered array of posts, introducing disorder can also promote chaotic fluctuations. We provide a unifying explanation for these contrasting results by considering the effect of disorder on the occurrence of stagnation points exposed to the flow field, which depends on the nature of the originally ordered post array. This work provides a general understanding of how pore geometry affects the stability of viscoelastic porous media flows.
AB - Viscoelastic flows through porous media become unstable and chaotic beyond critical flow conditions, impacting widespread industrial and biological processes such as enhanced oil recovery and drug delivery. Understanding the influence of the pore structure or geometry on the onset of flow instability can lead to fundamental insights into these processes and, potentially, to their optimization. Recently, for viscoelastic flows through porous media modeled by arrays of microscopic posts, Walkama et al. [D. M. Walkama, N. Waisbord, J. S. Guasto, Phys. Rev. Lett. 124, 164501 (2020)] demonstrated that geometric disorder greatly suppressed the strength of the chaotic fluctuations that arose as the flow rate was increased. However, in that work, disorder was only applied to one originally ordered configuration of posts. Here, we demonstrate experimentally that, given a slightly modified ordered array of posts, introducing disorder can also promote chaotic fluctuations. We provide a unifying explanation for these contrasting results by considering the effect of disorder on the occurrence of stagnation points exposed to the flow field, which depends on the nature of the originally ordered post array. This work provides a general understanding of how pore geometry affects the stability of viscoelastic porous media flows.
KW - Elastic turbulence
KW - Porous media
KW - Stagnation point
KW - Viscoelastic fluid
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U2 - 10.1073/pnas.2111651118
DO - 10.1073/pnas.2111651118
M3 - Article
C2 - 34521756
AN - SCOPUS:85115298752
SN - 0027-8424
VL - 118
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 38
M1 - e2111651118
ER -