Turbulent Convection at Very High Rayleigh Numbers and the Weakly Nonlinear Theory
نویسندگان
چکیده
To provide insights into the challenging problem of turbulent convection, Jack Herring used a greatly truncated version complete Boussinesq equations containing only one horizontal wavenumber. In light later observations robust large-scale circulation sweeping through convecting enclosures at high Rayleigh numbers, it is perhaps not an implausible point view from which to reexamine high-Rayleigh-number data. Here we compare past experimental data on convective heat transport numbers with predictions Herring’s model and, in fact, find excellent agreement. The has unknown parameter compared two free parameters present lowest-order least-squares power-law fit. We discuss why underlying simplistic physical picture, meant work slightly critical value few thousand, consistent when single revised, over some eleven decades number—stretching about million 1017.
منابع مشابه
Turbulent convection at high Rayleigh numbers and aspect ratio 4
We report measurements of the Nusselt number, Nu, in turbulent thermal convection in a cylindrical container of aspect ratio 4. The highest Rayleigh number achieved was Ra=2× 10. Except for the last half a decade or so of Ra, experimental conditions obey the Boussinesq approximation accurately. For these conditions, the data show that the logNu–logRa slope saturates at a value close to 1/3, as ...
متن کاملBoundary layers in rotating weakly turbulent Rayleigh–Bénard convection
Richard J. A. M. Stevens, Herman J. H. Clercx, and Detlef Lohse Department of Science and Technology and J. M. Burgers Center for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands Department of Applied Mathematics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands and Department of Physics and J. M. Burgers Centre for Fluid Dynamics, Eindh...
متن کاملComment on "Effect of boundary layers asymmetry on heat transfer efficiency in turbulent Rayleigh-Bénard convection at very high Rayleigh numbers".
In turbulent Rayleigh-Bénard convection (a fluid between two parallel horizontal plates and heated from below) a transition was predicted to occur [1,2] with increasing Rayleigh number Ra from a ‘‘classical’’ state with laminar boundary layers (BLs) to an ‘‘ultimate’’ state with turbulent BLs. Recently, this transition was found in measurements of the Nusselt number Nu and Reynolds number Re as...
متن کاملOn the nature of fluctuations in turbulent Rayleigh–Bénard convection at large Prandtl numbers
We report experimental results for the power spectra, variance, skewness and kurtosis of temperature fluctuations in turbulent Rayleigh–Bénard convection (RBC) of a fluid with Prandtl number Pr= 12.3 in cylindrical samples with aspect ratios Γ (diameter D over height L) of 0.50 and 1.00. The measurements were primarily for the radial positions ξ = 1− r/(D/2)= 1.00 and ξ = 0.063. In both cases, ...
متن کاملExperimental study of non-Boussinesq Rayleigh–Bénard convection at high Rayleigh and Prandtl numbers
A set of experiments is performed, in which a layer of fluid is heated from below and cooled from above, in order to study convection at high Rayleigh numbers ~Ra! and Prandtl numbers ~Pr!. The working fluid, corn syrup, has a viscosity that depends strongly on temperature. Viscosity within the fluid layer varies by a factor of 6 to 1.8310 in the various experiments. A total of 28 experiments a...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Atmosphere
سال: 2023
ISSN: ['2073-4433']
DOI: https://doi.org/10.3390/atmos14050826