Advectional enhancement of eddy diffusivity under parametric disorder

Abstract

Frozen parametric disorder can lead to 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 delocalization of convective currents, both numerically and analytically; and report subsequent drastic boost of the effective diffusivity for weak advection.

14 pages, 6 figures, for Topical Issue of Physica Scripta "2nd Intl. Conf. on Turbulent Mixing and Beyond"

References in corpus (6)

• Destruction of Anderson localization by a weak nonlinearity
• Robustness of the noise-induced phase synchronization in a general class of limit cycle oscillators
• Localization and advectional spreading of convective currents under parametric disorder
• Large-Scale Thermal Convection in a Horizontal Porous Layer
• Diffusion of a passive scalar by convective flows under parametric disorder
• Advectional enhancement of eddy diffusivity under parametric disorder

Cited by in corpus (4)

• Localization and advectional spreading of convective currents under parametric disorder
• High-Order Schemes of Exponential Time Differencing for Stiff Systems with Nondiagonal Linear Part
• Two scenarios of advective washing-out of localized convective patterns under frozen parametric disorder
• Advectional enhancement of eddy diffusivity under parametric disorder