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Equilibrium transport in double-diffusive convection

Published online by Cambridge University Press:  28 September 2011

Timour Radko  and
D. Paul Smith
Timour Radko*
Affiliation:
Department of Oceanography, Naval Postgraduate School, Monterey, CA 93943, USA
D. Paul Smith
Affiliation:
Department of Oceanography, Naval Postgraduate School, Monterey, CA 93943, USA
*
†Email address for correspondence: tradko@nps.edu
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Abstract

A theoretical model for the equilibrium double-diffusive transport is presented which emphasizes the role of secondary instabilities of salt fingers in saturation of their linear growth. Theory assumes that the fully developed equilibrium state is characterized by the comparable growth rates of primary and secondary instabilities. This assumption makes it possible to formulate an efficient algorithm for computing diffusivities of heat and salt as a function of the background property gradients and molecular parameters. The model predicts that the double-diffusive transport of heat and salt rapidly intensifies with decreasing density ratio. Fluxes are less sensitive to molecular characteristics, mildly increasing with Prandtl number and decreasing with diffusivity ratio . Theory is successfully tested by a series of direct numerical simulations which span a wide range of and .

JFM classification

Convection: Double diffusive convection Instability: Instability Geophysical and Geological Flows: Ocean processes
Type
Papers
Information
Journal of Fluid Mechanics , Volume 692 , 10 February 2012 , pp. 5 - 27
Copyright
Copyright © Cambridge University Press 2011

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