Oscillatory thermal-inertial flows in liquid metal rotating convection

Tobias Vogt, Susanne Horn, Jonathan M. Aurnou

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    3 Citations (Scopus)
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    Abstract

    We present the first detailed thermal and velocity field characterization of convection in a rotating cylindrical tank of liquid gallium, which has thermophysical properties similar to those of planetary core fluids. Our laboratory experiments, and a closely associated direct numerical simulation, are all carried out in the regime prior to the onset of steady convective modes. This allows us to study the oscillatory convective modes, sidewall modes and broadband turbulent flow that develop in liquid metals before the advent of steady columnar modes. Our thermo-velocimetric measurements show that strongly inertial, thermal wind flows develop, with velocities reaching those of non-rotating cases. Oscillatory bulk convection and wall modes coexist across a wide range of our experiments, along with strong zonal flows that peak in the Stewartson layer, but that extend deep into the fluid bulk in the higher supercriticality cases. The flows contain significant time-mean helicity that is anti-symmetric across the midplane, demonstrating that oscillatory liquid metal convection contains the kinematic components to sustain system-scale dynamo generation.

    Original languageEnglish
    Article numberA5
    Number of pages29
    JournalJournal of Fluid Mechanics
    Volume911
    Early online date25 Jan 2021
    DOIs
    Publication statusPublished - 25 Mar 2021

    Bibliographical note

    This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

    Keywords

    • geodynamo
    • rotating flows

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering

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