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Ekman-Hartmann Boundary Layers and the Length of Day Variations

Published online by Cambridge University Press:  19 July 2016

N. Kleeorin
Affiliation:
Department of Mechanical Engineering, Ben-Gurion University of Negev, POB 653, 84105 Beer-Sheva, Israel
I. Rogachevskii
Affiliation:
Racah Institute of Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
A. Ruzmaikin
Affiliation:
Isaac Newton Institute for Mathematical Sciences, Cambridge University, 20 Clarkson Road, CB2 0EH, Cambridge, U.K.

Extract

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In the first issue of Journal of Fluid Mechanics Ian Proudman published a paper on the dynamical properties of a fluid between two concentric rotating spheres (Proudman, 1956). The angular velocities of the spheres were assumed only slightly different and the Reynolds number of the flow was large. It was found under non-slip boundary conditions that the cylindrical surface that touches the inner sphere and parallel to the axis of rotation is a singular surface in which velocity gradients are very large. Outside the cylinder the fluid rotates as a rigid body with the same angular velocity as the outer sphere. Inside the cylinder the fluid rotates with an angular velocity intermediate to the angular velocities of the spheres and there is also a meridional circulation. Later Stewartson (1966) presented a detailed investigation of structure of the shear layer near the cylindrical surface. One of the present authors (Ruzmaikin, 1989) pointed out a possible geophysical importance of these solutions. The liquid part of the Earth core occupying a shell between the inner solid core and the rock mantle can be considered as the fluid between two rotating spheres.

Type
10. Geodynamo and Planetary Dynamos
Copyright
Copyright © Kluwer 1993 

References

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