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We extend the ideas of Kolmogorov theory on symmetries of turbulent dynamics to analyze invariants, scaling and spectra of unsteady turbulent mixing induced by the Rayleigh-Taylor instability. Time- and scale-invariance of the rate of…

Plasma Physics · Physics 2010-04-28 Snezhana I. Abarzhi

We investigate the structures of the near-plate velocity and temperature profiles at different horizontal positions along the conducting bottom (and top) plate of a Rayleigh-B\'{e}nard convection cell, using two-dimensional (2D) numerical…

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

We study turbulent natural convection in enclosures with conjugate heat transfer. The simplest way to increase the heat transfer in this flow is through rough surfaces. In numerical simulations often the constant temperature is assigned at…

Fluid Dynamics · Physics 2017-01-25 Paolo Orlandi , Sergio Pirozzoli

We propose a closure model for the transport of entropy and momentum in astrophysical turbulence, intended for application to rotating stellar convective regions. Our closure model is first presented in the Boussinesq formalism, and…

Solar and Stellar Astrophysics · Physics 2015-05-18 Pascale Garaud , Gordon I. Ogilvie , Neil Miller , Stephan Stellmach

Flame instabilities play a dominant role in accelerating the burning front to a large fraction of the speed of sound in a Type Ia supernova. We present a three-dimensional numerical simulation of a Rayleigh-Taylor unstable carbon flame,…

Astrophysics · Physics 2009-11-10 M. Zingale , S. E. Woosley , C. A. Rendleman , M. S. Day , J. B. Bell

New insight into the contribution of the microscale vortex evolution towards convection heat transfer in porous media is presented in this paper. The objective is to determine how the microscale vortices influence convection heat transfer…

Fluid Dynamics · Physics 2022-06-01 Ching-Wei Huang , Vishal Srikanth , Andrey V. Kuznetsov

This paper presents a nonlinear reaction-diffusion-fluid system that simulates radiofrequency ablation within cardiac tissue. The model conveys the dynamic evolution of temperature and electric potential in both the fluid and solid regions,…

Numerical Analysis · Mathematics 2024-05-03 Mostafa Bendahmane , Youssef Ouakrim , Yassine Ouzrour , Mohamed Zagour

By tailoring the geometry of the upper boundary in turbulent Rayleigh-B\'enard convection we manipulate the boundary layer -- interior flow interaction, and examine the heat transport using the Lattice Boltzmann method. For fixed amplitude…

Fluid Dynamics · Physics 2015-09-14 Srikanth Toppaladoddi , Sauro Succi , John S. Wettlaufer

Direct numerical simulations have been performed for turbulent thermal convection between horizontal no-slip, permeable walls with a distance $H$ and a constant temperature difference $\Delta T$ at the Rayleigh number…

Fluid Dynamics · Physics 2020-04-21 Koki Kawano , Shingo Motoki , Masaki Shimizu , Genta Kawahara

A Lagrangian fluctuation-dissipation relation has been derived in a previous work to describe the dissipation rate of advected scalars, both passive and active, in wall-bounded flows. We apply this relation here to develop a Lagrangian…

Fluid Dynamics · Physics 2018-03-15 Gregory L. Eyink , Theodore D. Drivas

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 analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of…

Astrophysics · Physics 2011-02-11 David Arnett , Casey Meakin , P. A. Young

Horizontally extended plane-layer convection flows are characterized by characteristic patterns of turbulent heat transfer due to the convective fluid motion consisting of a nearly-regular ridge network where hot fluid rises and cold fluid…

Fluid Dynamics · Physics 2025-10-08 Aleksandar Badza , Gary Froyland , Roshan J. Samuel , Jörg Schumacher

Radiative mixing layers arise wherever multiphase gas, shear, and radiative cooling are present. Simulations show that in steady state, thermal advection from the hot phase balances radiative cooling. However, many features are puzzling.…

Astrophysics of Galaxies · Physics 2021-07-12 Brent Tan , S. Peng Oh , Max Gronke

Thermal convection in fluid layers heated from below are usually realized experimentally as well as treated theoretically with fixed boundaries on which conditions for the temperature and the velocity field are prescribed. The thermal and…

Fluid Dynamics · Physics 2011-02-08 R. D. Simitev , F. H. Busse

The spectra of turbulent heat flux $\mathrm{H}(k)$ in Rayleigh-B\'{e}nard convection with and without uniform rotation are presented. The spectrum $\mathrm{H}(k)$ scales with wave number $k$ as $\sim k^{-2}$. The scaling exponent is almost…

Fluid Dynamics · Physics 2016-05-23 Hirdesh K. Pharasi , Deepesh Kumar , Krishna Kumar , Jayanta K. Bhattacharjee

Convection is a fundamental fluid transport phenomenon, where the large-scale motion of a fluid is driven, for example, by a thermal gradient or an electric potential. Modeling convection has given rise to the development of chaos theory…

Computational Physics · Physics 2021-08-17 Yifei Guan , Steven L. Brunton , Igor Novosselov

For years, astrophysicists, plasma fusion and fluid physicists have puzzled over Rayleigh-Taylor turbulent mixing layers. In particular, strong discrepancies in the growth rates have been observed between experiments and numerical…

Fluid Dynamics · Physics 2015-05-13 Olivier Poujade , Mathieu Peybernes

Convective overshoot mixing is a critical ingredient of stellar structure models, but is treated in most cases by ad hoc extensions of the mixing-length theory for convection. Advanced theories which are both more physical and numerically…

Solar and Stellar Astrophysics · Physics 2022-11-16 Felix Ahlborn , Friedrich Kupka , Achim Weiss , Martin Flaskamp