English
Related papers

Related papers: Bounds for convection between rough boundaries

200 papers

In this study, we investigate the coupling effects of roughness and wall shear in an annular centrifugal Rayleigh-B\'enard convection (ACRBC) system, where two cylinders rotate with different angular velocities. Two-dimensional direct…

Fluid Dynamics · Physics 2025-01-28 Fan Xu , Jun Zhong , Jinghong Su , Bidan Zhao , Yurong He , Chao Sun , Junwu Wang

Albeit laboratory experiments and numerical simulations have proven themselves successful in enhancing our understanding of long-living large-scale flow structures in horizontally extended Rayleigh-B\'enard convection, some discrepancies…

Fluid Dynamics · Physics 2025-02-12 Philipp Patrick Vieweg , Theo Käufer , Christian Cierpka , Jörg Schumacher

We study the navigation of a self-propelled inertial particle in two-dimensional Rayleigh--B\'enard convection at Prandtl number $Pr = 0.71$ and cell aspect ratio $\Gamma = 4$ for Rayleigh numbers $Ra$ ranging from $10^{7}$ to $10^{11}$. A…

Fluid Dynamics · Physics 2026-04-17 Ao Xu , Hua-Lin Wu , Ben-Rui Xu , Heng-Dong Xi

We numerically investigate turbulent Rayleigh-B\'enard convection with gas bubbles attached to the hot plate, mimicking a core feature in electrolysis, catalysis, or boiling. The existence of bubbles on the plate reduces the global heat…

Fluid Dynamics · Physics 2022-08-17 Hao-Ran Liu , Kai Leong Chong , Rui Yang , Roberto Verzicco , Detlef Lohse

We perform direct numerical simulations of an unstably stratified turbulent channel flow to address the effects of buoyancy on the boundary layer dynamics and mean field quantities. We systematically span a range of parameters in the space…

Fluid Dynamics · Physics 2022-06-13 Andrea Scagliarini , Halldór Einarsson , Ármann Gylfason , Federico Toschi

A systematic theory for the scaling of the Nusselt number $Nu$ and of the Reynolds number $Re$ in strong Rayleigh-Benard convection is suggested and shown to be compatible with recent experiments. It assumes a coherent large scale…

chao-dyn · Physics 2017-05-17 Siegfried Grossmann , Detlef Lohse

We consider an internally heated fluid between parallel plates with fixed thermal fluxes. For a large class of heat sources that vary in the direction of gravity, we prove that $\langle\delta T \rangle_h \geq \sigma R^{-1/3} - \mu$, where…

Fluid Dynamics · Physics 2024-11-20 Ali Arslan , Giovanni Fantuzzi , John Craske , Andrew Wynn

Gravity-driven convection of fluid at parameters near its thermodynamic critical point inside a porous layer heated from below (Rayleigh-Darcy convection) is studied. The fluid having the temperature slightly above the critical one is…

Fluid Dynamics · Physics 2010-01-26 E. B. Soboleva

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

In this paper we estimate the relative strengths of various terms of the Rayleigh-B\'enard equations. Based on these estimates and scaling analysis, we derive a general formula for the large-scale velocity, $U$, or the P\'eclet number that…

Fluid Dynamics · Physics 2016-11-29 Ambrish Pandey , Abhishek Kumar , Anando G. Chatterjee , Mahendra K. Verma

In this work, a near-wall model, which couples the inverse of a recently developed compressible velocity transformation [Griffin, Fu, & Moin, PNAS, 118:34, 2021] and an algebraic temperature-velocity relation, is developed for high-speed…

Fluid Dynamics · Physics 2023-09-11 Kevin Patrick Griffin , Lin Fu , Parviz Moin

Turbulent superstructures in horizontally extended three-dimensional Rayleigh-B\'enard convection flows are investigated in controlled laboratory experiments in water at Prandtl number $Pr = 7$. A Rayleigh-B\'enard cell with square…

Fluid Dynamics · Physics 2022-08-03 Sebastian Moller , Theo Käufer , Ambrish Pandey , Jörg Schumacher , Christian Cierpka

The heat transfer and flow structure in rotating Rayleigh-B\'enard convection are strongly influenced by the Rayleigh ($Ra$), Prandtl ($Pr$), and Rossby ($Ro$) number. For $Pr\gtrsim 1$ and intermediate rotation rates, the heat transfer is…

Fluid Dynamics · Physics 2020-05-14 Yantao Yang , Roberto Verzicco , Detlef Lohse , Richard J. A. M. Stevens

Previous numerical studies on homogeneous Rayleigh-B\'enard convection, which is Rayleigh-B\'enard convection (RBC) without walls, and therefore without boundary layers, have revealed a scaling regime that is consistent with theoretical…

Fluid Dynamics · Physics 2018-06-22 Chong Shen Ng , Andrew Ooi , Detlef Lohse , Daniel Chung

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

In turbulent wall sheared thermal convection, there are three different flow regimes, depending on the relative relevance of thermal forcing and wall shear. In this paper we report the results of direct numerical simulations of such sheared…

In thermal convection, roughness is often used as a means to enhance heat transport, expressed in Nusselt number. Yet there is no consensus on whether the Nusselt vs. Rayleigh number scaling exponent ($\mathrm{Nu} \sim \mathrm{Ra}^\beta$)…

Fluid Dynamics · Physics 2017-10-18 Xiaojue Zhu , Richard J. A. M. Stevens , Roberto Verzicco , Detlef Lohse

We develop innovative analytical expressions for the mean wind and potential temperature flux profiles in convective boundary layers (CBLs). CBLs are frequently observed during daytime as the Earth's surface is warmed by solar radiation.…

Fluid Dynamics · Physics 2023-08-07 Luoqin Liu , Srinidhi N. Gadde , Richard J. A. M. Stevens

The non-hydrostatic, quasigeostrophic approximation for rapidly rotating Rayleigh-B\'enard convection admits a class of exact `single mode' solutions. These solutions correspond to steady laminar convection with a separable structure…

Fluid Dynamics · Physics 2015-06-03 Ian Grooms

Turbulent Rayleigh-B\'{e}nard convection is often modelled with a constant surface temperature. However, the surface temperature of many geophysical systems, such as lakes, is coupled to the atmospheric forcing. In this paper, we account…

Fluid Dynamics · Physics 2023-03-14 Jason Olsthoorn