Regimes of Coriolis-Centrifugal Convection

Susanne Horn, Jonathan M. Aurnou

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Centrifugal buoyancy affects all rotating turbulent convection phenomena, but is conventionally ignored in rotating convection studies. Here, we include centrifugal buoyancy to investigate what we call Corioliscentrifugal convection (C3), characterizing two so far unexplored regimes, one where the flow is in
quasicyclostrophic balance (QC regime) and another where the flow is in a triple balance between pressure gradient, Coriolis and centrifugal buoyancy forces (CC regime). The transition to centrifugally dominated dynamics occurs when the Froude number Fr equals the radius-to-height aspect ratio γ. Hence, turbulent
convection experiments with small γ may encounter centrifugal effects at lower Fr than traditionally expected. Further, we show analytically that the direct effect of centrifugal buoyancy yields a reduction of the Nusselt number Nu. However, indirectly, it can cause a simultaneous increase of the viscous dissipation
and thereby Nu through a change of the flow morphology. These direct and indirect effects yield a net Nu suppression in the CC regime and a net Nu enhancement in the QC regime. In addition, we demonstrate that C3 may provide a simplified, yet self-consistent, model system for tornadoes, hurricanes, and typhoons.
Original languageEnglish
Article number204502
Number of pages5
JournalPhysical Review Letters
Volume120
DOIs
Publication statusPublished - 15 May 2018
Externally publishedYes

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buoyancy
convection
typhoons
tornadoes
hurricanes
Froude number
Nusselt number
pressure gradients
encounters
aspect ratio
retarding
radii
augmentation
causes

Bibliographical note

© 2018 American Physical Society
Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders.

Cite this

Regimes of Coriolis-Centrifugal Convection. / Horn, Susanne; Aurnou, Jonathan M.

In: Physical Review Letters, Vol. 120, 204502, 15.05.2018.

Research output: Contribution to journalArticle

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N2 - Centrifugal buoyancy affects all rotating turbulent convection phenomena, but is conventionally ignored in rotating convection studies. Here, we include centrifugal buoyancy to investigate what we call Corioliscentrifugal convection (C3), characterizing two so far unexplored regimes, one where the flow is inquasicyclostrophic balance (QC regime) and another where the flow is in a triple balance between pressure gradient, Coriolis and centrifugal buoyancy forces (CC regime). The transition to centrifugally dominated dynamics occurs when the Froude number Fr equals the radius-to-height aspect ratio γ. Hence, turbulentconvection experiments with small γ may encounter centrifugal effects at lower Fr than traditionally expected. Further, we show analytically that the direct effect of centrifugal buoyancy yields a reduction of the Nusselt number Nu. However, indirectly, it can cause a simultaneous increase of the viscous dissipationand thereby Nu through a change of the flow morphology. These direct and indirect effects yield a net Nu suppression in the CC regime and a net Nu enhancement in the QC regime. In addition, we demonstrate that C3 may provide a simplified, yet self-consistent, model system for tornadoes, hurricanes, and typhoons.

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