Confinement and dynamical regulation in two-dimensional convective turbulence

Bian, N.H. and Garcia, O.E. (2003) Confinement and dynamical regulation in two-dimensional convective turbulence. Physics of Plasmas, 10(12), pp. 4696-4707. (doi:10.1063/1.1625941)

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Abstract

In this work the nature of confinement improvement implied by the self-consistent generation of mean flows in two-dimensional convective turbulence is studied. The confinement variations are linked to two distinct regulation mechanisms which are also shown to be at the origin of low-frequency bursting in the fluctuation level and the convective heat flux integral, both resulting in a state of large-scale intermittency. The first one involves the control of convective transport by sheared mean flows. This regulation relies on the conservative transfer of kinetic energy from tilted fluctuations to the mean component of the flow. Bursting can also result from the quasi-linear modification of the linear instability drive which is the mean pressure gradient. For each bursting process the relevant zero-dimensional model equations are given. These are finally coupled in a minimal model of convection in fluids and plasmas. The results of the modeling are used to discuss confinement scaling and intermittency, and in a heuristic way, more complex issues such as criticality and transport avalanches.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Bian, Dr Nicolas Horace
Authors: Bian, N.H., and Garcia, O.E.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physics of Plasmas
Publisher:American Institute of Physics
ISSN:1070-664X
ISSN (Online):1089-7674

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