Скачать или смотреть Rotational dynamics of planetary cores: from geostrophic to inertial wave turbulence

By Benjamin Favier, IRPHÉ, Aix-Marseille Université, CNRS & École Centrale MarseilleIn this lecture, we discuss the properties of confined rotating turbulence at low Rossby number combining experimental and numerical approaches.
We are in particular interested in the dynamics of small liquid planetary cores, which might not be convectively unstable, but are nevertheless mechanically forced due to gravitational interactions with orbiting companions.
Experimentally, we are interested in the flow inside an ellipsoidal container mechanically forced by a harmonic perturbation of its rotation rate (libration forcing). We discuss various aspects of this system, from the elliptic instability mechanism involving resonances of inertial modes to the turbulent saturation involving both waves and vortices. In a second part, an idealized local Cartesian model is introduced in order to further explore the small-scale homogeneous dynamics. This tool allows us to reach unexplored regimes in terms of Rossby and Ekman numbers, and highlights/confirms the existence of an inertial wave turbulence regime. We conclude with a brief discussion involving applications to planetary cores, dynamo action and links with more classical homogeneous rotating turbulence.

New Challenges in Turbulence Research V (NCTR5)
École de Physique des Houches, April 7-12, 2019
http://nctr.eu/
(presentation available on the school website)