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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…

The design of film cooling systems relies heavily on Reynolds-Averaged Navier-Stokes (RANS) simulations, which solve for mean quantities and model all turbulent scales. Most turbulent heat flux models, which are based on isotropic diffusion…

Fluid Dynamics · Physics 2019-10-09 Pedro M. Milani , Julia Ling , John K. Eaton

Rayleigh-B\'enard convection is numerically simulated in two- and three-dimensions using a recently developed two-component lattice Boltzmann equation (LBE) method. The density field of the second component, which evolves according to the…

comp-gas · Physics 2016-08-31 Xiaowen Shan

We study numerically the melting of a horizontal layer of a pure solid above a convecting layer of its fluid rotating about the vertical axis. In the rotating regime studied here, with Rayleigh numbers of order $10^7$, convection takes the…

Fluid Dynamics · Physics 2021-04-13 S. Ravichandran , J. S. Wettlaufer

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

We investigate the influence of the thermal properties of the boundaries in turbulent Rayleigh-Benard convection on analytical bounds on convective heat transport. Using the Doering-Constantin background flow method, we systematically…

Fluid Dynamics · Physics 2008-11-20 Ralf W. Wittenberg

Turbulent motions enhance the diffusion of large-scale flows and temperature gradients. Such diffusion is often parameterized by coefficients of turbulent viscosity ($\nu_{\rm t}$) and turbulent thermal diffusivity ($\chi_{\rm t}$) that are…

Fluid Dynamics · Physics 2022-12-07 Petri J. Käpylä , Nishant K. Singh

We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia…

Analysis of PDEs · Mathematics 2015-06-12 Christian Seis

We investigate the miscible Rayleigh-Taylor (RT) instability in both 2 and 3 dimensions using direct numerical simulations, where the working fluid is assumed incompressible under the Boussinesq approximation. We first consider the case of…

Fluid Dynamics · Physics 2015-06-26 Y. Young , H. Tufo , A. Dubey , R. Rosner

The phenomenon of turbulent thermal diffusion in temperature-stratified turbulence causing a non-diffusive turbulent flux of inertial and non-inertial particles in the direction of the turbulent heat flux is found using direct numerical…

Solar and Stellar Astrophysics · Physics 2012-11-28 N. E. L. Haugen , N. Kleeorin , I. Rogachevskii , A. Brandenburg

We present an experimental study of Rayleigh-B\'enard convection using liquid metal alloy gallium-indium-tin as the working fluid with a Prandtl number of $Pr=0.029$. The flow state and the heat transport were measured in a Rayleigh number…

Fluid Dynamics · Physics 2023-08-01 Lei Ren , Xin Tao , Lu Zhang , Ming-Jiu Ni , Ke-Qing Xia , Yi-Chao Xie

Rigorous upper limits on the vertical heat transport in two dimensional Rayleigh-Benard convection between stress-free isothermal boundaries are derived from the Boussinesq approximation of the Navier-Stokes equations. The Nusselt number Nu…

Fluid Dynamics · Physics 2015-05-27 Jared P. Whitehead , Charles R. Doering

Spontaneous transitions between non-equilibrium patterns are characterised by hydrodynamic calculations of ideal straight roll steady state heat convection. The calculations are tested quantitatively against existing experimental data. It…

Statistical Mechanics · Physics 2012-08-28 Phil Attard

Raylaigh-Benard convection is one of the most well-studied models in fluid mechanics. Atmospheric convection, one of the most important components of the climate system, is by comparison complicated and poorly understood. A key attribute of…

Atmospheric and Oceanic Physics · Physics 2019-01-30 Geoffrey K. Vallis , Douglas J. Parker , Steven M. Tobias

The Rayleigh-Taylor (RT) instability develops and leads to turbulence when a heavy fluid falls under the action of gravity through a light one. We consider this phenomenon accompanied by a reactive transformation between the fluids, and…

Fluid Dynamics · Physics 2015-05-13 M. Chertkov , V. Lebedev , N. Vladimirova

Turbulent thermal diffusion is a combined effect of the temperature stratified turbulence and inertia of small particles. It causes the appearance of a non-diffusive turbulent flux of particles in the direction of the turbulent heat flux.…

Fluid Dynamics · Physics 2018-05-24 G. Amir , N. Bar , A. Eidelman , T. Elperin , N. Kleeorin , I. Rogachevskii

Reservoir computing is applied to model the large-scale evolution and the resulting low-order turbulence statistics of a two-dimensional turbulent Rayleigh-B\'{e}nard convection flow at a Rayleigh number ${\rm Ra}=10^7$ and a Prandtl number…

Fluid Dynamics · Physics 2020-11-25 Sandeep Pandey , Jörg Schumacher

Pushing two fluids with different density one against the other causes the development of the Rayleigh-Taylor instability at their interface, which further evolves in a complex mixing layer. In porous media, this process is influenced by…

Fluid Dynamics · Physics 2020-06-15 G. Boffetta , M. Borgnino , S. Musacchio

A novel phase field method is proposed to model the continuous transition of binary fluids exhibiting temperature sensitive miscibility gap, from immiscible state to miscible state via partially miscible states. The model is employed to…

Fluid Dynamics · Physics 2025-08-28 Anubhav Dubey , Constantin Habes , Holger Marschall , Sakir Amiroudine

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