The global characteristics of the three-dimensional thermal convection inside a spherical shell

The Rayleigh number-Nusselt number, and the Rayleigh number-thermal boundary layer thickness relationships are determined for the three-dimensional convection in a spherical shell of constant physical parameters. Several models are considered with Rayleigh numbers ranging from 1.1...

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Main Author: J. Arkani-Hamed
Format: Article
Language:English
Published: Copernicus Publications 1997-01-01
Series:Nonlinear Processes in Geophysics
Online Access:http://www.nonlin-processes-geophys.net/4/19/1997/npg-4-19-1997.pdf
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author J. Arkani-Hamed
author_facet J. Arkani-Hamed
author_sort J. Arkani-Hamed
collection DOAJ
description The Rayleigh number-Nusselt number, and the Rayleigh number-thermal boundary layer thickness relationships are determined for the three-dimensional convection in a spherical shell of constant physical parameters. Several models are considered with Rayleigh numbers ranging from 1.1 x 10<em><sup>2</sup></em> to 2.1 x 10<em><sup>5</sup></em> times the critical Rayleigh number. At lower Rayleigh numbers the Nusselt number of the three-dimensional convection is greater than that predicted from the boundary layer theory of a horizontal layer but agrees well with the results of an axisymmetric convection in a spherical shell. At high Rayleigh numbers of about 10<sup><em>5</em> </sup> times the critical value, which are the characteristics of the mantle convection in terrestrial planets, the Nusselt number of the three-dimensional convection is in good agreement with that of the boundary layer theory. At even higher Rayleigh numbers, the Nusselt number of the three-dimensional convection becomes less than those obtained from the boundary layer theory. The thicknesses of the thermal boundary layers of the spherical shell are not identical, unlike those of the horizontal layer. The inner thermal boundary is thinner than the outer one, by about 30- 40%. Also, the temperature drop across the inner boundary layer is greater than that across the outer boundary layer.
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spelling doaj.art-a07f315ecd3c4e8990dbf6facd30daba2022-12-21T23:56:42ZengCopernicus PublicationsNonlinear Processes in Geophysics1023-58091607-79461997-01-01411927The global characteristics of the three-dimensional thermal convection inside a spherical shellJ. Arkani-HamedThe Rayleigh number-Nusselt number, and the Rayleigh number-thermal boundary layer thickness relationships are determined for the three-dimensional convection in a spherical shell of constant physical parameters. Several models are considered with Rayleigh numbers ranging from 1.1 x 10<em><sup>2</sup></em> to 2.1 x 10<em><sup>5</sup></em> times the critical Rayleigh number. At lower Rayleigh numbers the Nusselt number of the three-dimensional convection is greater than that predicted from the boundary layer theory of a horizontal layer but agrees well with the results of an axisymmetric convection in a spherical shell. At high Rayleigh numbers of about 10<sup><em>5</em> </sup> times the critical value, which are the characteristics of the mantle convection in terrestrial planets, the Nusselt number of the three-dimensional convection is in good agreement with that of the boundary layer theory. At even higher Rayleigh numbers, the Nusselt number of the three-dimensional convection becomes less than those obtained from the boundary layer theory. The thicknesses of the thermal boundary layers of the spherical shell are not identical, unlike those of the horizontal layer. The inner thermal boundary is thinner than the outer one, by about 30- 40%. Also, the temperature drop across the inner boundary layer is greater than that across the outer boundary layer.http://www.nonlin-processes-geophys.net/4/19/1997/npg-4-19-1997.pdf
spellingShingle J. Arkani-Hamed
The global characteristics of the three-dimensional thermal convection inside a spherical shell
Nonlinear Processes in Geophysics
title The global characteristics of the three-dimensional thermal convection inside a spherical shell
title_full The global characteristics of the three-dimensional thermal convection inside a spherical shell
title_fullStr The global characteristics of the three-dimensional thermal convection inside a spherical shell
title_full_unstemmed The global characteristics of the three-dimensional thermal convection inside a spherical shell
title_short The global characteristics of the three-dimensional thermal convection inside a spherical shell
title_sort global characteristics of the three dimensional thermal convection inside a spherical shell
url http://www.nonlin-processes-geophys.net/4/19/1997/npg-4-19-1997.pdf
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