Intermittent Lagrangian velocities and accelerations in three-dimensional porous medium flow.
Intermittency of Lagrangian velocity and acceleration is a key to understanding transport in complex systems ranging from fluid turbulence to flow in porous media. High-resolution optical particle tracking in a three-dimensional (3D) porous medium provides detailed 3D information on Lagrangian velocities and accelerations. We find sharp transitions close to pore throats, and low flow variability in the pore bodies, which gives rise to stretched exponential Lagrangian velocity and acceleration distributions characterized by a sharp peak at low velocity, superlinear evolution of particle dispersion, and double-peak behavior in the propagators. The velocity distribution is quantified in terms of pore geometry and flow connectivity, which forms the basis for a continuous-time random-walk model that sheds light on the observed Lagrangian flow and transport behaviors.
Institute of Environmental Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 15, 8093 Zürich, Switzerland.
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M
Holzner
SIMBIOS Centre, University of Abertay, Bell Street Dundee DD1 1HG, United Kingdom.
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VL
Morales
Institute of Environmental Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 15, 8093 Zurich, Switzerland.
M
M
Willmann
Spanish National Research Council (IDAEA-CSIC), c/Jordi Girona 18, 08034 Barcelona, Spain.
M
M
Dentz
D019840:2-Propanol; D005465:Fluorocarbon Polymers; D057446:Hydrodynamics; D008962:Models, Theoretical; D016062:Porosity; D014057:Tomography, X-Ray Computed; D014867:Water
D005465:Fluorocarbon Polymers; D014867:Water; C040402:perfluorosulfonic acid; D019840:2-Propanol