Turbulent Thermal Convection

Fonda, Enrico; Sreenivasan, Katepalli R.

doi:10.1007/978-3-319-11487-3_2

Cited by 1 publication

(1 citation statement)

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“…While realistic atmospheric conditions are characterized by Rayleigh numbers between O(10 18 ) and O(10 22 ), this is far above the level of turbulence that direct numerical simulations can resolve at present, which are closer to Ra ; 10 10 (Plumley and Julien 2019), which for Pr 5 1 corresponds to Ra f between 10 13.3 and 10 15 , depending on how the heat transport scales with Ra (Aurnou et al 2020). Such forcings would be expected to yield Reynolds numbers Re ; 10 4 (Fonda and Sreenivasan 2015).…”

Section: A Governing Equations and Parameter Regimementioning

confidence: 99%

Large-Scale Circulations and Dry Tropical Cyclones in Direct Numerical Simulations of Rotating Rayleigh–Bénard Convection

Velez-Pardo

Cronin

2023

Journal of the Atmospheric Sciences

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The organization of convection into relatively long-lived patterns of large spatial scales, like tropical cyclones, is a common feature of the Earth’s atmosphere. However, many key aspects of convective aggregation and its relationship with tropical cyclone formation remain elusive. In this work, we simulate highly idealized setups of dry convection, inspired by the Rayleigh-Bénard system, to probe the effects of different thermal boundary conditions on the scale of organization of rotating convection, and on the formation of tropical-cyclone-like structures. We find that in domains with sufficiently high aspect ratios, moderately turbulent (Raf ≳ 109), moderately rotating (Roc ≳ 1) convection organizes more persistently and at larger scales when thermal boundary conditions constrain heat fluxes rather than temperatures. Furthermore, for some thermal boundary conditions with asymmetric heat fluxes, convection organizes into persistent vortices with the essential properties of mature tropical cyclones: a warm core, high axisymmetry, a strong azimuthal circulation, and substantially larger size than individual buoyant plumes. We argue that flux asymmetry results in a persistent and localized input of buoyancy which allows spatially aggregated convection to sustain a warm core in a developing large-scale vortex. Crucially, the most intense and axisymmetric cyclone forms for setups where the bottom heat flux is enhanced by the nearby flow and the top boundary is insulating, as long as the convective Rossby number is higher than about 1. Our results demonstrate the great potential for dialogue between classical turbulence research and the study of convective aggregation and tropical cyclones.

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Section: A Governing Equations and Parameter Regimementioning

confidence: 99%