Summary: Axisymmetric simulations of libration-driven fluid dynamics in a spherical
shell geometry
Michael A. Calkins,1,a
Jérôme Noir,2
Jeff D. Eldredge,1
and Jonathan M. Aurnou2
1
Department of Mechanical and Aerospace Engineering, University of California, Los Angeles,
California 90095, USA
2
Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA
Received 6 April 2010; accepted 29 June 2010; published online 26 August 2010
We report on axisymmetric numerical simulations of rapidly rotating spherical shells in which the
axial rotation rate of the outer shell is modulated in time. This allows us to model planetary bodies
undergoing forced longitudinal libration. In this study we systematically vary the Ekman number,
10-7
E 10-4
, which characterizes the ratio of viscous to Coriolis forces in the fluid, and the
libration amplitude, . For libration amplitudes above a certain threshold, Taylor­Görtler vortices
form near the outer librating boundary, in agreement with the previous laboratory experiments of

Source: Aurnou, Jonathan - Department of Earth and Space Sciences, University of California at Los Angeles

Collections: Geosciences