Measured oscillations of the velocity and temperature fields in turbulent Rayleigh-Bénard convection in a rectangular cell

Abstract

Temperature and velocity oscillations have been found in a rectangular Rayleigh-Bénard convection cell, in which one large scale convection roll exists. At $Ra=8.9\times 10^{11}$ and $Pr=4$, temperature oscillation can be observed in most part of the system and the oscillation period remains almost constant, $t_T=74\pm 2$ seconds. Velocity oscillation can only be found in its horizontal component, $v_y$ (perpendicular to large scale circulation plane), near the cell sidewall, its oscillation period is also constant, $t_T=65\pm 2$ seconds, at these positions. Temperature and velocity oscillations have different Ra dependence, which are respectively indicated by Peclect number $P{e}_T=0.55R{a}^{0.47}$ and $P{e}_v=0.28R{a}^{0.50}$ . In comparison to the case of cylindrical cell, we find that the velocity oscillation is affected by the system geometry.

arXiv comment6 pages, 6 figures. submitted to PRE

References in corpus (3)

• Rotations and cessations of the large-scale circulation in turbulent Rayleigh-Benard convection
• Plume motion and large-scale circulation in a cylindrical Rayleigh-Bénard cell
• High Rayleigh number turbulent convection in a gas near the gas-liquid critical point

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• A low-dimensional model predicting geometry-dependent dynamics of large-scale coherent structures in turbulence
• Tristable flow states and reversal of the large-scale circulation in two-dimensional circular convection cells
• Comparative experimental study of local mixing of active and passive scalars in turbulent thermal convection