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arXiv · 2512.11669

The Persistent Clock of Turbulent Thermal Convection

Lázaro Martínez-Ortíz·Youri H. Lemm·Herman J. H. Clercx·Rudie P. J. Kunnen
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Abstract

The large-scale circulation (LSC) of turbulent convection is a prominent feature of its dynamics and forms the basis for descriptive theories. We show, using experimental and numerical results from thermal convection in a cylindrical cell, that the LSC possesses a persistent internal `clock': its pulsating velocity as a function of time is described by a constant value of the parameter U/(lf) where U is the mean velocity, f the pulsation frequency, and l the characteristic length scale. By introducing a narrow sidewall barrier, we can trip the LSC, forming a pair of interconnected rolls stacked above and below the barrier. They independently exhibit the same value for the ratio U/(lf), even for vertically asymmetric pairs, indicating signs of synchrony. Thus, this parameter establishes a direct connection between plume-shedding dynamics and the flow topology.

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Lázaro Martínez-Ortíz, Youri H. Lemm, Herman J. H. Clercx, Rudie P. J. Kunnen. 2025-12-12. The Persistent Clock of Turbulent Thermal Convection. https://arxiv.org/abs/2512.11669

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