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Related papers: Bounds on Rayleigh-B\'enard convection with imperf…

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We propose an analytical model to estimate the interface temperature $\Theta_{\Gamma}$ and the Nusselt number $Nu$ for an evaporating two-layer Rayleigh-B\'enard configuration in statistically stationary conditions. The model is based on…

Fluid Dynamics · Physics 2023-03-22 Nicoló Scapin , Andreas D. Demou , Luca Brandt

Steady but generally unstable solutions of the 2D Boussinesq equations are obtained for no-slip boundary conditions and Prandtl number 7. The primary solution that bifurcates from the conduction state at Rayleigh number $Ra \approx 1708$…

Fluid Dynamics · Physics 2015-06-11 Fabian Waleffe , Anakewit Boonkasame , Leslie M. Smith

We report high-precision measurements of the Nusselt number $Nu$ as a function of the Rayleigh number $Ra$ in water-filled rectangular Rayleigh-B\'{e}nard convection cells. The horizontal length $L$ and width $W$ of the cells are 50.0 cm…

Fluid Dynamics · Physics 2015-06-05 Quan Zhou , Bo-Fang Liu , Chun-Mei Li , Bao-Chang Zhong

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

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

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 dynamics of heat transfer in a model system of Rayleigh-B\'enard (RB) convection reduced to its essential, here dubbed Burgers-Rayleigh-B\'enard (BRB), is studied. The system is spatially one-dimensional, the flow field is compressible…

Fluid Dynamics · Physics 2023-07-04 Enrico Calzavarini , Silvia C. Hirata

We present highly resolved measurements of the near-wall temperature field in thermally driven convection at a rough surface. Our measurements have been undertaken in a very large experimental facility called the "Barrel of Ilmenau". They…

Fluid Dynamics · Physics 2018-04-17 Ronald du Puits , Alice Loesch , Julien Salort , Francesca Chillà

Many natural and industrial turbulent flows are subjected to time-dependent boundary conditions. Despite being ubiquitous, the influence of temporal modulations (with frequency $f$) on global transport properties has hardly been studied.…

Fluid Dynamics · Physics 2020-10-14 Rui Yang , Kai Leong Chong , Qi Wang , Roberto Verzicco , Olga Shishkina , Detlef Lohse

Bounds for the poloidal and toroidal kinetic energies and the heat transport are computed numerically for rotating convection at infinite Prandtl number with both no slip and stress free boundaries. The constraints invoked in this…

Fluid Dynamics · Physics 2022-08-30 A. Tilgner

Boiling is an extremely effective way to promote heat transfer from a hot surface to a liquid due to several mechanisms many of which are not understood in quantitative detail. An important component of the overall process is that the…

Heat and momentum transfer in wall-bounded turbulent flow, coupled with the effects of wall-roughness, is one of the outstanding questions in turbulence research. In the standard Rayleigh-B\'enard problem for natural thermal convection, it…

Fluid Dynamics · Physics 2019-07-05 Michael MacDonald , Nicholas Hutchins , Detlef Lohse , Daniel Chung

Two-dimensional direct numerical simulations are conducted for convection sustained by uniform internal heating in a horizontal fluid layer. Top and bottom boundary temperatures are fixed and equal. Prandtl numbers range from 0.01 to 100,…

Fluid Dynamics · Physics 2015-03-13 David Goluskin , Edward A. Spiegel

We study turbulent Rayleigh-B\'enard convection over four decades of Rayleigh numbers 4E8 < Ra < 2E12, while harmonically modulating the temperatures of the plates of our cylindrical cell. We probe the flow by temperature sensors placed in…

Fluid Dynamics · Physics 2022-04-13 P. Urban , P. Hanzelka , T. Králík , V. Musilová , L. Skrbek

Steady two-dimensional Rayleigh--B\'enard convection between stress-free isothermal boundaries is studied via numerical computations. We explore properties of steady convective rolls with aspect ratios $\pi/5\le\Gamma\le4\pi$, where…

Fluid Dynamics · Physics 2021-06-30 Baole Wen , David Goluskin , Matthew LeDuc , Gregory P. Chini , Charles R. Doering

A Rayleigh-B\'enard cell has been designed to explore the Prandtl (Pr) dependence of turbulent convection in the cross-over range $0.7<Pr<21$ and for the full range of soft and hard turbulences, up to Rayleigh number $Ra\simeq 10^{11}$. The…

Condensed Matter · Physics 2009-11-10 P. -E. Roche , B. Castaing , B. Chabaud , B. Hebral

We perform a two-dimensional numerical study on the thermal effect of porous media on global heat transport and flow structure in Rayleigh-B\'enard (RB) convection, focusing on the role of thermal conductivity $\lambda$ of porous media,…

Fluid Dynamics · Physics 2023-04-17 Jun Zhong , Shuang Liu , Chao Sun

We report experimental results for the influence of a tilt angle beta relative to gravity on turbulent Rayleigh-Benard convection of cylindrical samples. The measurements were made at Rayleigh numbers R up to 10^11 with two samples of…

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

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

Results on the Prandtl-Blasius type kinetic and thermal boundary layer thicknesses in turbulent Rayleigh-B\'enard convection in a broad range of Prandtl numbers are presented. By solving the laminar Prandtl-Blasius boundary layer equations,…

Fluid Dynamics · Physics 2015-03-19 Olga Shishkina , Richard J. A. M. Stevens , Siegfried Grossmann , Detlef Lohse