Showing papers on "Shell balance published in 1983"

Differential rotation produced by potential vorticity mixing in a rapidly rotating fluid

Abstract: Summary. The differential rotation of a rapidly rotating spherical shell of incompressible fluid of low viscosity subject to large-scale mixing is investigated by considering the dynamical behaviour of axial filaments of fluid. Owing to the gyroscopic constraints expressed by the Proudman-Taylor theorem and the Ertel theorem, each filament retains its coherence and undergoes little change in its potential vorticity over time-scales of typical displacements perpendicular to the rotation axis. The form of the profile of the latitudinal variation of the mean zonal flow velocity depends on several factors, including the coupling between the fluid shell and the underlying surface and the thickness of the shell, strong positive jets being found near the equator when the fluid shell is thin and at mid-latitudes when the shell is thick. It is’remarkable that such a simple model can reproduce many of the observed features of the differential rotation of the Earth, Jupiter, Saturn and the Sun.