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Related papers: Thermal Radiation in Rayleigh-B\'{e}nard Convectio…

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We investigate the influence of the temperature boundary conditions at the sidewall on the heat transport in Rayleigh-B\'enard (RB) convection using direct numerical simulations. For relatively low Rayleigh numbers Ra the heat transport is…

Fluid Dynamics · Physics 2014-12-24 Richard J. A. M. Stevens , Detlef Lohse , Roberto Verzicco

Weakly-rotating turbulent Rayleigh-Benard convection was studied experimentally and numerically. With increasing rotation and large enough Rayleigh number an abrupt transition from a turbulent state with nearly rotation-independent heat…

Turbulent thermal convection is characterized by the formation of large-scale structures and strong spatial inhomogeneity. This work addresses the relative heat transport contributions of the large-scale plume ejecting versus plume…

Fluid Dynamics · Physics 2021-04-09 Philipp Reiter , Olga Shishkina , Detlef Lohse , Dominik Krug

We use well resolved numerical simulations with the Lattice Boltzmann Method to study Rayleigh-B\'enard convection in cells with a fractal boundary in two dimensions for $Pr = 1$ and $Ra \in \left[10^7, 10^{10}\right]$. The fractal…

Fluid Dynamics · Physics 2020-11-25 Srikanth Toppaladoddi , Andrew J. Wells , Charles R. Doering , John S. Wettlaufer

Direct numerical simulations of turbulent convection at high Rayleigh numbers in large aspect ratio cells are challenging because of the prohibitive computational resources required. One can achieve high Rayleigh numbers at affordable costs…

Fluid Dynamics · Physics 2021-10-28 Ambrish Pandey , Katepalli R. Sreenivasan

We report an experimental study aiming to clarify the role of boundary conditions (BC) in high Rayleigh number $10^8 < {\rm{Ra}} < 3 \times 10^{12}$ turbulent thermal convection of cryogenic helium gas. We switch between BC closer to…

Fluid Dynamics · Physics 2021-08-11 P. Urban , T. Králík , M. Macek , P. Hanzelka , T. Věžník \and L. Skrbek

Boundary layers play an important role in controlling convective heat transfer. Their nature varies considerably between different application areas characterized by different boundary conditions, which hampers a uniform treatment. Here, we…

Fluid Dynamics · Physics 2013-03-20 K. Petschel , S. Stellmach , M. Wilczek , J. Lülff , U. Hansen

We report on a three-dimensional direct numerical simulation study of flow structure and heat transport in the annular centrifugal Rayleigh-B\'{e}nard convection (ACRBC) system, with cold inner and hot outer cylinders corotating axially,…

Fluid Dynamics · Physics 2021-04-09 Dongpu Wang , Hechuan Jiang , Shuang Liu , Xiaojue Zhu , Chao Sun

We describe three apparatus, known as the large, medium, and small apparatus, used for high-precision measurements of the Nusselt number N as a function of the Rayleigh number R for cylindrical samples of fluid and present results…

Fluid Dynamics · Physics 2009-11-11 Eric Brown , Alexei Nikolaenko , Denis Funfschilling , Guenter Ahlers

The study of the transitions among different regimes in thermal convection has been an issue of paramount importance in fluid mechanics. While the bifurcations at low Rayleigh number, when the flow is laminar or moderately chaotic, have…

Fluid Dynamics · Physics 2023-05-29 Vincent Labarre , Stéphan Fauve , Sergio Chibbaro

We present high-precision measurements of the Nusselt number N as a function of the Rayleigh number R for cylindrical samples of water (Prandtl number sigma = 4.4) with a diameter D of 49.7 cm and heights L = 116.3, 74.6, and 50.6 cm, as…

Fluid Dynamics · Physics 2009-11-10 Alexei Nikolaenko , Eric Brown , Denis Funfschilling , Guenter Ahlers

We prove the first rigorous bound on the heat transfer for three-dimensional Rayleigh-B\'enard convection of finite-Prandtl-number fluids between free-slip boundaries with an imposed heat flux. Using the auxiliary functional method with a…

Fluid Dynamics · Physics 2018-04-11 Giovanni Fantuzzi

We present a theory to describe the Nusselt number ($Nu$), corresponding to the heat or mass flux, as a function of the Rayleigh--Darcy number ($Ra$), the ratio of buoyant driving force over diffusive dissipation, in convective porous media…

Fluid Dynamics · Physics 2024-11-20 Xiaojue Zhu , Yifeng Fu , Marco De Paoli

In Rayleigh-B\'enard convection, it has been found that the amount of heat passing through the fluid has a power law dependence on the imposed temperature difference. Modifying this dependence, either enhancing or reducing the heat transfer…

Fluid Dynamics · Physics 2022-10-14 Jinzi Mac Huang , Jun Zhang

We investigate the influence of the thermal properties of the boundaries in turbulent Rayleigh-B\'enard convection on analytical upper bounds on convective heat transport. We model imperfectly conducting bounding plates in two ways: using…

Fluid Dynamics · Physics 2010-08-17 Ralf W. Wittenberg

Direct Numerical Simulations of turbulent convection in a large aspect-ratio box are carried out in the range of Rayleigh number $7 \times 10^4 \le Ra \le 2 \times 10^6$ at Prandtl number Pr=0.71. A strong correlation between the vertical…

Fluid Dynamics · Physics 2017-08-09 Arnab K. De , Vinayak Eswaran , Pankaj K. Mishra

We report experimental results for heat-transport measurements by turbulent Rayleigh-B\'enard convection in a cylindrical sample of aspect ratio $\Gamma \equiv D/L = 1.00$ ($D = 1.12$ m is the diameter and $L = 1.12$ m the height). They are…

Fluid Dynamics · Physics 2015-06-05 Xiaozhou He , Denis Funfschilling , Eberhard Bodenschatz , Guenter Ahlers

Turbulent convection in the interiors of the Sun and the Earth occurs at high Rayleigh numbers $Ra$, low Prandtl numbers $Pr$, and different levels of rotation rates. To understand the combined effects better, we study rotating turbulent…

Fluid Dynamics · Physics 2024-11-20 Ambrish Pandey , Katepalli R. Sreenivasan

The aspect ratio (\Gamma) dependence of the heat transfer (Nusselt number Nu in dimensionless form) in turbulent (two-dimensional) Rayleigh-B\'enard convection is numerically studied in the regime $0.4 \le \Gamma \le 1.25$ for Rayleigh…

Fluid Dynamics · Physics 2011-12-05 Erwin P. van der Poel , Richard J. A. M. Stevens , Detlef Lohse

We present results of numerical investigation on thermal flux in Rayleigh-B\'{e}nard magnetoconvection in the presence of a uniform vertical magnetic field. We have studied thermal flux in different viscous fluids with a range of Prandtl…

Fluid Dynamics · Physics 2020-08-28 Sandip Das , Krishna Kumar