Revisiting Reynolds and Nusselt numbers in turbulent thermal convection
نویسندگان
چکیده
In this paper, we extend Grossmann and Lohse’s (GL) model [S. D. Lohse, “Thermal convection for large Prandtl numbers,” Phys. Rev. Lett. 86, 3316 (2001)] the predictions of Reynolds number (Re) Nusselt (Nu) in turbulent Rayleigh–Bénard convection. Toward objective, use functional forms prefactors dissipation rates bulk boundary layers. The arise due to inhibition nonlinear interactions presence walls buoyancy compared free turbulence, along with a deviation viscous layer profile from Prandtl–Blasius theory. We perform 60 numerical runs on three-dimensional unit box range Rayleigh numbers (Ra) (Pr) determine aforementioned using machine learning. revised are better agreement past experimental results than those GL model, especially extreme numbers.
منابع مشابه
Nusselt number measurements for turbulent Rayleigh-Bénard convection.
We present high-precision measurements of the Nusselt number N as a function of the Rayleigh number R for a cylindrical sample of water (Prandtl number sigma=4.4) of height L approximately equal to 50 cm and aspect ratio Gamma identical with D/L approximately equal to 1 (D is the diameter) for 3 x 10(9)< or =R< or =6 x 10(10). For R approximately 3 x 10(9) the data are consistent with existing ...
متن کاملLarge-scale flow and Reynolds numbers in the presence of boiling in locally heated turbulent convection
Paul B. J. Hoefnagels,1,2 Ping Wei,3 Daniela Narezo Guzman,1,2 Chao Sun,1,4 Detlef Lohse,1,5 and Guenter Ahlers2 1Physics of Fluids Group, Department of Science and Technology, J.M. Burgers Center for Fluid Dynamics, Mesa+-Institute, and Max Planck Center Twente, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands 2Department of Physics, University of California, Santa Barbara...
متن کاملPrandtl and Rayleigh number dependence of the Reynolds number in turbulent thermal convection.
The Prandtl and Rayleigh number dependences of the Reynolds number in turbulent thermal convection following from the unifying theory by Grossmann and Lohse [J. Fluid Mech. 407, 27 (2000); Phys. Rev. Lett. 86, 3316 (2001)] are presented and compared with various recent experimental findings. This dependence Re(Ra,Pr) is more complicated than a simple global power law. For Pr=5.5 and 10(8)<Ra<10...
متن کاملReynolds numbers of the large-scale flow in turbulent Rayleigh-Bénard convection
We measured Reynolds numbers Re of turbulent Rayleigh-Bénard convection over the Rayleighnumber range 2×10 <∼ R <∼ 10 11 and Prandtl-number range 3.3 <∼ σ <∼ 29 for cylindrical samples of aspect ratio Γ = 1. For R <∼ Rc ≃ 3× 10 9 we found Re ∼ R βeff with βeff ≃ 0.46 < 1/2. Here both the σand R-dependences are quantitatively consistent with the Grossmann-Lohse (GL) prediction. For R > Rc we fou...
متن کاملTurbulent pipe flow at extreme Reynolds numbers.
Both the inherent intractability and complex beauty of turbulence reside in its large range of physical and temporal scales. This range of scales is captured by the Reynolds number, which in nature and in many engineering applications can be as large as 10(5)-10(6). Here, we report turbulence measurements over an unprecedented range of Reynolds numbers using a unique combination of a high-press...
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: Physics of Fluids
سال: 2021
ISSN: ['1527-2435', '1089-7666', '1070-6631']
DOI: https://doi.org/10.1063/5.0032498