Monodisperse and polydisperse colloid transport in water-saturated fractures with various orientations: Gravity effectsMonodisperse and polydisperse colloid transport in water-saturated fractures with various orientations: Gravity effects
Peer-Reviewed Journal Publication
Δημοσίευση σε Περιοδικό με Κριτές
2015-09-192011enNumerical experiments are conducted to examine the effects of gravity on monodisperse and polydisperse
colloid transport in water-saturated fractures with uniform aperture. Dense colloids travel in
water-saturated fractures by advection and diffusion while subject to the influence of gravity. Colloids
are assumed to neither attach onto the fracture walls nor penetrate the rock matrix based on the assumptions
that they are inert and their size is larger than the pore size of the surrounding solid matrix. Both
the size distribution of a colloid plume and colloid density are shown to be significant factors impacting
their transport when gravitational forces are important. A constant-spatial-step particle-tracking code
simulates colloid plumes with increasing densities transporting in water-saturated fractures while
accounting for three forces acting on each particle: a deterministic advective force due to the Poiseuille
flow field within the fracture, a random force caused by Brownian diffusion, and the gravitational force.
Integer angles of fracture orientation with respect to the horizontal ranging from ±90 are considered:
three lognormally distributed colloid plumes with mean particle size of 1 lm (averaged on a volumetric
basis) and standard deviation of 0.6, 1.2 and 1.8 lm are examined. Colloid plumes are assigned densities
of 1.25, 1.5, 1.75 and 2.0 g/cm3. The first four spatial moments and the first two temporal moments are
estimated as functions of fracture orientation angle and colloid density. Several snapshots of colloid
plumes in fractures of different orientations are presented. In all cases, larger particles tend to spread
over wider sections of the fracture in the flow direction, but smaller particles can travel faster or slower
than larger particles depending on fracture orientation anglehttp://creativecommons.org/licenses/by/4.0/Advances in Water Resources34101249-1255A68-AWR-11.pdfChania [Greece]Library of TUC2015-09-19application/pdf1.2 MBfree
Chrysikopoulos Constantinos
Χρυσικοπουλος Κωνσταντινος
Scott C. James