ISSN:
1089-7666
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The dispersion of a passive tracer in a two-dimensional, spatially periodic stationary flow, such as convection rolls, is studied in the large Peclet number limit. In the case where injection, at time t=0, is localized in one roll, two regimes exist. First, there is an anomalous diffusion regime in which the number of invaded rolls grows like t1/3. This regime is due to the presence of separatrices between rolls that induce trapping of tracer within each roll. At a later time, when t(very-much-greater-than)Td (the diffusion time within a roll), the usual diffusion regime is recovered, yet with an effective diffusive coefficient κeff that is greater than the molecular diffusivity κ by a factor proportional to the square root of the Peclet number.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.857415
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