Dynamics and Statistics of Reorientations of Large-Scale Circulation in Turbulent Rotating Rayleigh-Bénard Convection

Abstract

We present a direct numerical simulation to investigate the dynamics and statistics of reorientations of large-scale circulation (LSC) in turbulent rotating Rayleigh-Bénard convection (RRBC) for air ($Pr=0.7$) contained in a cylindrical cell with unit aspect ratio. A wide range of rotation rates ($0\le R{o}^{-1}\le 30$) is considered for two different Rayleigh numbers $Ra=2\times 10^6$ and $2\times 10^7$. Using the Fourier mode analysis of time series data obtained from the different probes placed in the azimuthal direction of the container at the mid-plane, the orientation and associated dynamics of LSC are characterized. The amplitude of the first Fourier mode quantifies the strength of LSC and its phase ${\Phi }_1$ gives the information of the azimuthal orientation of LSC. Based on the energy contained in the Fourier modes different flow regimes are identified as the rotation rate is varied for a given Rayleigh number. LSC structure is observed in the low rotation regime ( $R{o}^{-1}\lesssim 1$). A strong correlation between the orientation of LSC structure and the heat transfer and boundary layer dynamics is observed. In the LSC regime, the dissipation rates follow the log-normal behaviour, while at higher rotation rates, a clear departure from log-normality is noticed. Different types of reorientations, namely, rotation-led, cessation-led, partial and complete reversal are identified. The distribution of change in orientation of LSC follows a power law behaviour as $P(|\Delta {\Phi }_1|)\propto |\Delta {\Phi }_1{|}^{-m}$, with the exponent $m\approx 3.7$. In addition, the statistics of time interval between successive reorientations follow a Poisson distribution. These observations are in good agreement with earlier experimental results.

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References in corpus (5)

• Rotations and cessations of the large-scale circulation in turbulent Rayleigh-Benard convection
• Origin of the Temperature Oscillation in Turbulent Thermal Convection
• Dynamics of reorientations and reversals of large scale flow in Rayleigh-Benard convection
• Flow reversals in turbulent convection with free-slip walls
• Extreme dissipation event due to plume collision in a turbulent convection cell

Cited by in corpus (3)

• Effects of tilt on the orientation dynamics of the large-scale circulation in turbulent Rayleigh-B{é}nard convection
• Effect of horizontal magnetic field on Küppers-Lortz instability
• Reorientation of large-scale circulation of turbulent Rayleigh-Bénard convection in a cubic cell