Absence of Evidence for the Ultimate State of Turbulent Rayleigh-Bénard Convection
نویسندگان
چکیده
منابع مشابه
Search for the "ultimate state" in turbulent Rayleigh-Bénard convection.
Measurements of the Nusselt number Nu and of temperature variations DeltaTb in the bulk fluid are reported for turbulent Rayleigh-Bénard convection of a cylindrical sample. They cover the Rayleigh-number range 10(9) less than or similar to Ra less than or similar to 3x10(14) using He (Prandtl number Pr=0.67), N2 (Pr=0.72) and SF6 (Pr=0.79 to 0.84) at pressures up to 15 bars and near-ambient tem...
متن کاملTransition to the ultimate state of turbulent Rayleigh-Bénard convection.
Measurements of the Nusselt number Nu and of a Reynolds number Re(eff) for Rayleigh-Bénard convection (RBC) over the Rayleigh-number range 10(12)≲Ra≲10(15) and for Prandtl numbers Pr near 0.8 are presented. The aspect ratio Γ≡D/L of a cylindrical sample was 0.50. For Ra≲10(13) the data yielded Nu∝Ra(γ(eff)) with γ(eff)≃0.31 and Re(eff)∝Ra(ζ(eff)) with ζ(eff)≃0.43, consistent with classical turb...
متن کاملUltimate-state transition of turbulent Rayleigh-Bénard convection
Guenter Ahlers,1,2,* Eberhard Bodenschatz,2,3,4,* and Xiaozhou He5,* 1Department of Physics, University of California, Santa Barbara, California 93106, USA 2Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany 3Institute for Nonlinear Dynamics, University of Göttingen, 37077 Göttingen, Germany 4Laboratory of Atomic and Solid-State Physics and Sibley School o...
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The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-Bénard convection is theoretically analyzed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range 10(-2)...
متن کاملThermal boundary layer equation for turbulent Rayleigh-Bénard convection.
We report a new thermal boundary layer equation for turbulent Rayleigh-Bénard convection for Prandtl number Pr>1 that takes into account the effect of turbulent fluctuations. These fluctuations are neglected in existing equations, which are based on steady-state and laminar assumptions. Using this new equation, we derive analytically the mean temperature profiles in two limits: (a) Pr≳1 and (b)...
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ژورنال
عنوان ژورنال: Physical Review Letters
سال: 2020
ISSN: 0031-9007,1079-7114
DOI: 10.1103/physrevlett.124.229401