Advectional enhancement of eddy diffusivity under parametric disorder

作者:Goldobin Denis S*
来源:Physica Scripta, 2010, T142: 014050.
DOI:10.1088/0031-8949/2010/T142/014050

摘要

Frozen parametric disorder can lead to the appearance of sets of localized convective currents in an otherwise stable (quiescent) fluid layer heated from below. These currents significantly influence the transport of an admixture (or any other passive scalar) along the layer. When the molecular diffusivity of the admixture is small in comparison to the thermal one, which is quite typical in nature, disorder can enhance the effective (eddy) diffusivity by several orders of magnitude in comparison to the molecular diffusivity. In this paper, we study the effect of an imposed longitudinal advection on the delocalization of convective currents, both numerically and analytically, and report a subsequent drastic boost of the effective diffusivity for weak advection.

  • 出版日期2010-12