Work

Internal heating in rapidly rotating convection is not a shortcut to geostrophic turbulence

Year: 2026

Type: preprint

Abstract: Convective turbulence in planets and stars is often driven by internal heating. This forcing mechanism has also been proposed as a means of accessing the diffusion-free scalings of the geostrophic turbulence (GT) regime at modest forcing. We test this with the asymptotically reduced quasi-geostrophic model, which is formally valid in the limit of vanishing Ekman number, $Ek \rightarrow 0$, and retains the Prandtl number as an independent parameter. We find no such shortcut: the Nusselt and Reynolds numbers are no closer to their diffusion-free predictions than in the boundary-heated case; the predicted $Pr^{-1/2}$ collapse fails over the range surveyed; and the prefactor depends on the form of the heating. Our no-slip/stress-free cases track the radiatively driven simulations of Hadjerci, Bouillaut, Miquel & Gallet (J. Fluid Mech., vol. 998, 2024, A9) case by case. Those simulations span only the narrow range of forcing over which the compensated Nusselt number is near its maximum within their geostrophic-turbulence criterion; across the wider range accessible to the reduced model it rises to that maximum and then falls by more than an order of magnitude while the flow remains rotationally constrained. We argue that bulk transport scalings are incomplete diagnostics of GT, whereas the saturation of the interior mean temperature gradient and of the vertical velocity kurtosis remain reliable indicators.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2608.28756

Authors: Nicoski, Justin A., Oliver, Tobias G., Maffei, Stefano, Calkins, Michael A.

Institutions: University of Colorado Boulder, ETH Zurich, Institute of Geophysics

Language: English

Topic: Fluid Dynamics and Turbulent Flows

Subfield: Computational Mechanics

Field: Engineering

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Purdue University, Colorado State University, University of Colorado Boulder, Office of Advanced Cyberinfrastructure

Awards: G1060868137, G1086261101, G1453181110, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, G2299875479, G2888034965, G3036665267, G3185749182, G3562386289, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), G4010157413, ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), G5367127336, G5424111711, G5464919783, CAREER: Unraveling the Multiscale Asymptotic Dynamics of Planetary Dynamos, CC* Compute: HPC Services for the Colorado State University System, G7115838204, G731264315, G7807307182, G7852733817, CC* Regional Computing: Enhancing Computing At Regional Schools in the Rocky Mountain Advanced Computing Consortium (RMACC), G8054170119, G8067353062, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI, G878072758

OpenAlex ID: W7204940496

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