Reversals in infinite-Prandtl-number Rayleigh-Bénard convection

Pandey, Ambrish ; Verma, Mahendra K. ; Barma, Mustansir (2018) Reversals in infinite-Prandtl-number Rayleigh-Bénard convection Physical Review E: covering statistical, nonlinear, biological, and soft matter physics, 98 (2). ISSN 2470-0045

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Official URL: http://doi.org/10.1103/PhysRevE.98.023109

Related URL: http://dx.doi.org/10.1103/PhysRevE.98.023109

Abstract

Using direct numerical simulations, we study the statistical properties of reversals in two-dimensional Rayleigh-Bénard convection for infinite Prandtl number. We find that the large-scale circulation reverses irregularly, with the waiting time between two consecutive genuine reversals exhibiting a Poisson distribution on long timescales, while the interval between successive crossings on short timescales shows a power-law distribution. We observe that the vertical velocities near the sidewall and at the center show different statistical properties. The velocity near the sidewall shows a longer autocorrelation and 1 / f 2 power spectrum for a wide range of frequencies, compared to shorter autocorrelation and a narrower scaling range for the velocity at the center. The probability distribution of the velocity near the sidewall is bimodal, indicating a reversing velocity field. We also find that the dominant Fourier modes capture the dynamics at the sidewall and at the center very well. Moreover, we show a signature of weak intermittency in the fluctuations of velocity near the sidewall by computing temporal structure functions.

Item Type:Article
Source:Copyright of this article belongs to American Physical Society.
ID Code:118918
Deposited On:04 Jun 2021 08:29
Last Modified:18 Nov 2022 10:23

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