Abstract
Steady laminar flows through porous media spontaneously generate Lagrangian chaos at pore scale, with qualitative implications for a range of transport, reactive, and biological processes. The characterization and understanding of mixing dynamics in these opaque environments is an outstanding challenge. We address this issue by developing a novel technique based upon high-resolution imaging of the scalar signature produced by push-pull flows through porous media samples. Owing to the rapid decorrelation of particle trajectories in chaotic flows, the scalar image measured outside the porous material is representative of in situ mixing dynamics. We present a theoretical framework for estimation of the Lyapunov exponent based on extension of Lagrangian stretching theories to correlated aggregation. This method provides a full characterization of chaotic mixing dynamics in a large class of porous materials.
- Received 4 September 2020
- Revised 13 November 2020
- Accepted 9 December 2020
DOI:https://doi.org/10.1103/PhysRevLett.126.034505
© 2021 American Physical Society
Physics Subject Headings (PhySH)
Video
Psychedelic View of Fluid in Porous Materials
Published 22 January 2021
Video from a new technique reveals the chaotic motion of a fluid flowing through a pile of gravel.
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