Institutional Repository
Technical University of Crete
Technical University of Crete
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| URI: | http://purl.tuc.gr/dl/dias/BD0AACBA-B776-4111-A9A2-2D3E041F9D5A | ||
| Year | 2011 | ||
| Type of Item | Peer-Reviewed Journal Publication | ||
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| Bibliographic Citation | S. C. James , C.V. Chrysikopoulos , "Monodisperse and polydisperse colloid transport in water-saturated fractures with various orientations: Gravity effects " ,Advanc. in Wat.Resou. ,vol.3,no.10, pp. 1249–1255,2011.doi : 10.1016/j.advwatres.2011.06.001 https://doi.org/ 10.1016/j.advwatres.2011.06.001 | ||
| Appears in Collections |
Numerical experiments are conducted to examine the effects of gravity on monodisperse and polydispersecolloid transport in water-saturated fractures with uniform aperture. Dense colloids travel inwater-saturated fractures by advection and diffusion while subject to the influence of gravity. Colloidsare assumed to neither attach onto the fracture walls nor penetrate the rock matrix based on the assumptionsthat they are inert and their size is larger than the pore size of the surrounding solid matrix. Boththe size distribution of a colloid plume and colloid density are shown to be significant factors impactingtheir transport when gravitational forces are important. A constant-spatial-step particle-tracking codesimulates colloid plumes with increasing densities transporting in water-saturated fractures whileaccounting for three forces acting on each particle: a deterministic advective force due to the Poiseuilleflow 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 volumetricbasis) and standard deviation of 0.6, 1.2 and 1.8 lm are examined. Colloid plumes are assigned densitiesof 1.25, 1.5, 1.75 and 2.0 g/cm3. The first four spatial moments and the first two temporal moments areestimated as functions of fracture orientation angle and colloid density. Several snapshots of colloidplumes in fractures of different orientations are presented. In all cases, larger particles tend to spreadover wider sections of the fracture in the flow direction, but smaller particles can travel faster or slowerthan larger particles depending on fracture orientation angle
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