Scalar Signatures of Chaotic Mixing in Porous Media

J. Heyman (1) , T. Le Borgne (1) , D. r. R Lester (2)

1 GR - Géosciences Rennes
2 RMIT University - Royal Melbourne Institute of Technology University

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 Lypapunov 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.

Domains: Physics [physics]

J. Heyman, T. Le Borgne, D. r. R Lester. Scalar Signatures of Chaotic Mixing in Porous Media. Physical Review Letters, 2021, 126 (3), ⟨10.1103/PhysRevLett.126.034505⟩. ⟨hal-03450736⟩