Abstract
We investigate, both experimentally and numerically, the fluid flow in a spherical shell with radius ratio ri/ro=2/3. Both spheres rotate about a common axis, with Ωi>Ωo. The basic state consists of a Stewartson layer situated on the tangent cylinder, the cylinder parallel to the axis of rotation and touching the inner sphere. If the differential rotation is sufficiently large, non-axisymmetric instabilities arise, with the wavenumber of the most unstable mode increasing with increasing overall rotation. In the increasingly supercritical regime, a series of mode transitions occurs in which the wavenumber decreases again. The experimental and numerical results are in good agreement regarding this basic sequence of mode transitions, and the numerics are then used to study some of the finer details of the solutions that could not be observed in the experiment.
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References
Busse, F.H.: Shear flow instabilities in rotating systems. J. Fluid Mech. 33, 577–589 (1968)
Dormy, E., Cardin, P., Jault, D.: MHD flow in a slightly differentially rotating spherical shell, with a conducting inner core, in a dipolar magnetic field. Earth Planet. Sci. Lett. 160, 15–30 (1998)
Duck, P.W., Foster, M.R.: Spin-up of homogeneous and stratified fluids. Ann. Rev. Fluid Mech. 33, 231–263 (2001).
Egbers, C., Rath, H.J.: The existence of Taylor vortices and wide-gap instabilities in spherical Couette flow. Acta Mech. 111, 125–140 (1995).
Früh, W.G., Read, P.L.: Experiments on a barotropic rotating shear layer. Part 1. Instability and steady vortices. J. Fluid Mech. 383, 143–173 (1999)
Hollerbach, R.: Magnetohydrodynamic Ekman and Stewartson layers in a rotating spherical shell. Proc. R. Soc. Lond. A 444, 333–346 (1994)
Hollerbach, R.: A spectral solution of the magneto-convection equations in spherical geometry. Int. J. Numer. Meth. Fluids 32, 773–797 (2000)
Hollerbach, R.: Instabilities of the Stewartson layer. Part 1. The dependence on the sign of Ro. J. Fluid Mech. 492, 289–302 (2003)
Stewartson, K.: On almost rigid rotations. Part 2. J. Fluid Mech. 26, 131–144 (1966)
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H.J.S. Fernando
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Hollerbach, R., Futterer, B., More, T. et al. Instabilities of the Stewartson layer Part 2. Supercritical mode transitions. Theor. Comput. Fluid Dyn. 18, 197–204 (2004). https://doi.org/10.1007/s00162-004-0125-5
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DOI: https://doi.org/10.1007/s00162-004-0125-5