HR: 1340h
AN: H23E-1475    [Abstracts]
TI: Yet Another Possible Mechanism for Anomalous Transport: Theory, Numerical Method, and Experiments
AU: * INOUE, J
EM: inoue@material.t.u-tokyo.ac.jp
AF: Dept. of Material Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656 Japan
AU: Chun, P
EM: chun@ohriki.t.u-tokyo.ac.jp
AF: Dept. of Civil Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656 Japan
AB: A new possible mechanism for anomalous transport is studied and a new numerical approach is presented based on the mechanism. The transport behavior of passive solute in a heterogeneous medium is generally found non-Fickian, and the plume cannot be described by a time-independent center of mass velocity and constant dispersion coefficients. As a result, most of the publications concerning the mechanism for the anomalous transport behavior put their basis on the existence of inhomogeneities. That is, variation in a velocity field is widely considered to be the source of the anomalous transport. In the present study, from the discussion of the general transport equation called continuous time random walk, we show that a transport remains normal even in an existence of a very low conductivity inhomogeneity (highly heterogeneous case) but that only the Newtonian feature of any fluid can make a transport anomalous. The numerical analysis method is developed by transforming the three-dimensional general transport equation to one-dimensional along a streamline. This modification is valid only if a transverse dispersivity is negligible compared to a longitudinal dispersivity. The validity of the theory and the numerical approach is confirmed through three types of tracer experiments. A tracer test through two parallel smooth plastic plates demonstrates that anomalous transport can be observed in a Newtonian fluid without any inhomogeneity. Tracer tests through uniform porous media filled with glass beads and parallel plates with non-permeable zone are compared to the results obtained with the present method.
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
DE: 1884 Water supply
DE: 1894 Instruments and techniques: modeling
SC: Hydrology [H]
MN: Fall Meeting 2005