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Results from direct numerical simulation for three-dimensional Rayleigh-B\'enard convection in samples of aspect ratio $\Gamma=0.23$ and $\Gamma=0.5$ up to Rayleigh number $Ra=2\times10^{12}$ are presented. The broad range of Prandtl…

Fluid Dynamics · Physics 2011-12-05 Richard J. A. M. Stevens , Detlef Lohse , Roberto Verzicco

This paper reviews results about free convection near a vertical flat plate embedded in some saturated porous medium. We focus on a third order autonomous differential equation that gives a special class of solutions called similarity…

Classical Analysis and ODEs · Mathematics 2007-05-23 B. Brighi , J. -D. Hoernel

Unlike solids, the heat transfer in fluids can be greatly enhanced due to the presence of convection. Under gravity, an unevenly distributed temperature field results in differences in buoyancy, driving fluid motion that is seen in…

Fluid Dynamics · Physics 2024-10-04 Jinzi Mac Huang , Jun Zhang

We present a model supported by simulation to explain the effect of temperature on the conduction threshold in disordered systems. Arrays with randomly distributed local thresholds for conduction occur in systems ranging from…

Disordered Systems and Neural Networks · Physics 2007-05-23 Klara Elteto , Eduard G. Antonyan , T. T. Nguyen , Heinrich M. Jaeger

The downward flow in a vertical duct with one heated and three thermally insulated walls is analyzed numerically using the two-dimensional approximation valid in the asymptotic limit of an imposed strong transverse magnetic field. The work…

Fluid Dynamics · Physics 2018-12-05 Xuan Zhang , Oleg Zikanov

We investigate the dynamics of a fluid layer subject to an imposed bottom heat flux and a top monotonically-increasing temperature profile driving horizontal convection. We use direct numerical simulations and consider a large range of…

Fluid Dynamics · Physics 2022-07-14 Louis-Alexandre Couston , Joseph Nandaha , Benjamin Favier

Many environmental flows arise due to natural convection at a vertical surface, from flows in buildings to dissolving ice faces at marine-terminating glaciers. We use three-dimensional direct numerical simulations of a vertical channel with…

Fluid Dynamics · Physics 2023-06-22 Christopher J. Howland , Chong Shen Ng , Roberto Verzicco , Detlef Lohse

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

We present results of a simulation study of inelastic hard-disks vibrated in a vertical container. An Event-Driven Molecular Dynamics method is developed for studying the onset of convection. Varying the relevant parameters (inelasticity,…

Statistical Mechanics · Physics 2016-08-31 Daniela Paolotti , Alain Barrat , Umberto Marini Bettolo Marconi , Andrea Puglisi

High-Rayleigh number convective turbulence is ubiquitous in many natural phenomena and in industries, such as atmospheric circulations, oceanic flows, flows in the fluid core of planets, and energy generations. In this work, we present a…

Fluid Dynamics · Physics 2022-01-05 Hechuan Jiang , Xiaojue Zhu , Dongpu Wang , Sander G. Huisman , Chao Sun

We prove new bounds on the heat flux out of the bottom boundary, $\mathcal{F}_B$, for a fluid at infinite Prandtl number, heated internally between isothermal parallel plates under two kinematic boundary conditions. In uniform internally…

Fluid Dynamics · Physics 2024-03-22 Ali Arslan , Ruben E. Rojas

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…

Temperature and velocity oscillations have been found in a rectangular Rayleigh-B\'{e}nard convection cell, in which one large scale convection roll exists. At $Ra=8.9 \times 10^{11}$ and $Pr=4$, temperature oscillation can be observed in…

Fluid Dynamics · Physics 2009-11-13 Sheng-Qi Zhou , Chao Sun , Ke-Qing Xia

Melting and, conversely, solidification processes in the presence of convection are key to many geophysical problems. An essential question related to these phenomena concerns the estimation of the (time-evolving) melting rate, which is…

Room-temperature (RT) conductivity of most candidates for solid electrolytes of miniaturized lithium-ion batteries is still 1-2 orders of magnitude below commercial requirements, therefore several approaches are being pursued aiming the…

Materials Science · Physics 2016-03-17 R. Mouta , C. W. A. Paschoal

We propose a phenomenological model for thermal convection at high Rayleigh numbers. It hypothesizes existence of a high-Reynolds-number turbulent boundary layer near each horizontal plate, which is shown to be convective. The convective…

Fluid Dynamics · Physics 2024-03-27 Chenning Tong

In this paper we study thermoconvective instabilities appearing in a fluid within a cylindrical annulus heated laterally. As soon as a horizontal temperature gradient is applied a convective state appears. As the temperature gradient…

Analysis of PDEs · Mathematics 2009-11-07 S. Hoyas , H. Herrero , A. M. Mancho

Convection in planetary mantles is in the so-called mixed heating mode; it is driven by heating from below, due to a hotter core, as well as heating from within, due to radiogenic heating and secular cooling. Thus, in order to model the…

Geophysics · Physics 2023-06-07 Amy L. Ferrick , Jun Korenaga

Subglacial lakes are isolated, cold-temperature and high-pressure water environments hidden under ice sheets, which might host extreme microorganisms. Here, we use two-dimensional direct numerical simulations in order to investigate the…

Fluid Dynamics · Physics 2021-03-15 Louis-Alexandre Couston

The central open question about Rayleigh--B\'enard convection -- buoyancy-driven flow in a fluid layer heated from below and cooled from above -- is how vertical heat flux depends on the imposed temperature gradient in the strongly…

Fluid Dynamics · Physics 2022-01-10 Baole Wen , David Goluskin , Charles R. Doering