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In this paper, we propose a space-dependent eddy thermal diffusivity model for turbulent vertical natural convection in a fluid between two infinite vertical walls at different temperatures. Using this model, we derive analytical results…

Fluid Dynamics · Physics 2026-04-01 Ho Yin Ng , Emily S. C. Ching

We report on experimental determinations of the temperature field in the interior (bulk) of turbulent Rayleigh-Benard convection for a cylindrical sample with aspect ratio (diameter over height) of 0.50, both in the classical and in the…

Fluid Dynamics · Physics 2015-06-19 Guenter Ahlers , Eberhard Bodenschatz , Xiaozhou He

We study the effects of Prandtl number $Pr$ and Rayleigh number $Ra$ in two-dimensional Rayleigh-B\'enard convection without boundaries, i.e. with periodic boundary conditions. In the limits of $Pr \to 0$ and $\infty$, we find that the…

Fluid Dynamics · Physics 2023-12-27 Philip Winchester , Vassilios Dallas , Peter D. Howell

We study the scaling properties of heat transfer $Nu$ in turbulent thermal convection at large Prandtl number $Pr$ using a quasi-linear theory. We show that two regimes arise, depending on the Reynolds number $Re$. At low Reynolds number,…

Chaotic Dynamics · Physics 2015-05-28 B. Dubrulle

Bounds on heat transfer have been the subject of previous studies concerning convection in the Boussinesq approximation: in the Rayleigh-B\'enard configuration, the first result obtained by \cite{howard63} states that $Nu < (3/64 \…

Fluid Dynamics · Physics 2024-03-08 T. Alboussière , Y. Ricard , S. Labrosse

We investigate the convective stability of a thin, infinite fluid layer with a rectangular cross-section, subject to imposed heat fluxes at the top and bottom and fixed temperature along the vertical sides. The instability threshold depends…

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

The amount and spatial pattern of heat extracted from cores of terrestrial planets is ultimately controlled by the thermal structure of the lower rocky mantle. Using the most common model to tackle this problem, a rapidly rotating and…

Earth and Planetary Astrophysics · Physics 2016-01-26 Wieland Dietrich , Kumiko Hori , Johannes Wicht

Results from direct numerical simulations of vertical natural convection at Rayleigh numbers $1.0\times 10^5$-$1.0\times 10^9$ and Prandtl number $0.709$ support a generalised applicability of the Grossmann-Lohse (GL) theory, which was…

Fluid Dynamics · Physics 2018-06-21 Chong Shen Ng , Andrew Ooi , Detlef Lohse , Daniel Chung

We present a systematic investigation of the effects of roughness geometry on turbulent Rayleigh-B\'enard convection (RBC) over rough plates with pyramid-shaped and periodically distributed roughness elements. Using a parameter $\lambda$…

Fluid Dynamics · Physics 2017-07-26 Yi-Chao Xie , Ke-Qing Xia

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 present high-resolution numerical investigations of heat transport by two-dimensional (2D) turbulent Rayleigh-B\'{e}nard (RB) convection over the Rayleigh number range $10^8 \leqslant Ra\leqslant 10^{10}$ and the Prandtl number range…

Fluid Dynamics · Physics 2015-06-17 Yong-Xiang Huang , Quan Zhou

The frequency spectra of the entropy and kinetic energy along with the power spectrum of the thermal flux are computed from direct numerical simulations for turbulent Rayleigh-B\'{e}nard convection with uniform rotation about a vertical…

Fluid Dynamics · Physics 2014-11-11 Hirdesh K. Pharasi , Krishna Kumar , Jayanta K. Bhattacharjee

(abridged) Context: The ratio of kinematic viscosity to thermal diffusivity, the Prandtl number, is much smaller than unity in stellar convection zones. Aims: To study the statistics of convective flows and energy transport as functions of…

Solar and Stellar Astrophysics · Physics 2021-11-24 Petri J. Käpylä

Turbulent Rayleigh-Benard convection with phase changes in an extended layer between two parallel impermeable planes is studied by means of three-dimensional direct numerical simulations for Rayleigh numbers between 10^4 and 1.5\times 10^7…

Fluid Dynamics · Physics 2012-07-27 Thomas Weidauer , Joerg Schumacher

The structure of the boundary layers in turbulent Rayleigh-Benard convection is studied by means of three-dimensional direct numerical simulations. We consider convection in a cylindrical cell at an aspect ratio one for Rayleigh numbers of…

Fluid Dynamics · Physics 2012-09-04 Nan Shi , Mohammad S. Emran , Joerg Schumacher

Rayleigh-Benard convection in a cylindrical container can take on many different spatial forms. Motivated by the results of Hof, Lucas and Mullin [Phys. Fluids 11, 2815 (1999)], who observed coexistence of several stable states at a single…

Fluid Dynamics · Physics 2010-04-02 Katarayna Borońska , Laurette S. Tuckerman

We discuss two aspects of turbulent Rayleigh-B\'{e}nard convection (RBC) on the basis of high-resolution direct numerical simulations in a unique setting; a closed cylindrical cell of aspect ratio of one. First, we present a comprehensive…

Fluid Dynamics · Physics 2017-11-29 Janet D. Scheel , Jörg Schumacher

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

Direct Numerical Simulation have been carried out for a two dimensional flow in a Lid driven cavity at Reynolds number 5000 and Prandtl number 7 with water as the working fluid. Both the side walls of the enclosure are insulated(i.e.…

Fluid Dynamics · Physics 2022-09-08 Aditya Shankar Garg , Ishan Singh