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In thermal convection for very large Rayleigh numbers ($Ra$), the thermal and viscous boundary layers (BL) undergo a transition from a classical state to an ultimate state. In the former state, the BL thicknesses follow a laminar-like…

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

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…

Rayleigh-Benard convection in a rotating spherical shell provides a simplified model for convective dynamics of planetary and stellar interiors. In this study, we build more than 200 numerical models of rotating convection in a spherical…

Fluid Dynamics · Physics 2025-08-14 Wei Fan , Qi Wang , Yufeng Lin

We present a theory to describe the Nusselt number ($Nu$), corresponding to the heat or mass flux, as a function of the Rayleigh--Darcy number ($Ra$), the ratio of buoyant driving force over diffusive dissipation, in convective porous media…

Fluid Dynamics · Physics 2024-11-20 Xiaojue Zhu , Yifeng Fu , Marco De Paoli

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

We present highly resolved measurements of the near-wall temperature field in thermally driven convection at a rough surface. Our measurements have been undertaken in a very large experimental facility called the "Barrel of Ilmenau". They…

Fluid Dynamics · Physics 2018-04-17 Ronald du Puits , Alice Loesch , Julien Salort , Francesca Chillà

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

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

We report pore-scale statistical properties of temperature and thermal energy dissipation rate in a two-dimensional porous Rayleigh-B\'enard (RB) cell. High-resolution direct numerical simulations were carried out for the fixed Rayleigh…

Fluid Dynamics · Physics 2023-09-20 Ao Xu , Ben-Rui Xu , Heng-Dong Xi

Employing numerical simulations, we provide an accurate insight into the of heat transfer mechanisms in the Rayleigh-B\'enard convection of concentrated emulsions with finite-size droplets. We focus on the unsteady dynamics characterizing…

Fluid Dynamics · Physics 2024-02-14 Francesca Pelusi , Stefano Ascione , Mauro Sbragaglia , Massimo Bernaschi

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

We investigate the influence of the thermal properties of the boundaries in turbulent Rayleigh-B\'enard convection on analytical upper bounds on convective heat transport. We model imperfectly conducting bounding plates in two ways: using…

Fluid Dynamics · Physics 2010-08-17 Ralf W. Wittenberg

A theoretical study is presented in this paper to investigate the conjugate heat transfer across a vertical finite wall separating two forced and free convection flows at different temperatures. The heat conduction in the wall is in the…

Fluid Dynamics · Physics 2015-09-15 Jian-Jun Shu , I. Pop

Direct numerical simulations are carried out to investigate the effect of the wall temperature on the behavior of oblique shock-wave/turbulent boundary layer interactions at freestream Mach number $2.28$ and shock angle of the wedge…

Fluid Dynamics · Physics 2016-06-15 Matteo Bernardini , Johan Larsson , Sergio Pirozzoli , Francesco Grasso

We studied flow organization and heat transfer properties in mixed turbulent convection within Poiseuille-Rayleigh-B\'enard channels subjected to temporally modulated sinusoidal wall temperatures. Three-dimensional direct numerical…

Fluid Dynamics · Physics 2025-03-12 Ao Xu , Rui-Qi Li , Heng-Dong Xi

This study explores heat and turbulent modulation in three-dimensional multiphase Rayleigh-B\'enard convection using direct numerical simulations. Two immiscible fluids with identical reference density undergo systematic variations in…

Fluid Dynamics · Physics 2024-08-26 Abbas Moradi Bilondi , Nicolò Scapin , Luca Brandt , Parisa Mirbod

To understand how internal flow structures manifest themselves in the global heat transfer, we study the correlation between different flow modes and the instantaneous Nusselt number ($Nu$) in a two-dimensional square Rayleigh-B\'enard…

Fluid Dynamics · Physics 2020-10-09 Ao Xu , Xin Chen , Feng Wang , Heng-Dong Xi

We consider Rayleigh-B\'enard convection in a layer of fluid between rough no-slip boundaries where the top and bottom boundary heights are functions of the horizontal coordinates with square-integrable gradients. We use the background…

Fluid Dynamics · Physics 2016-10-20 David Goluskin , Charles R. Doering

We report on a numerical study of turbulent convection driven by a combination of internal heat sources and sinks. Motivated by a recent experimental realisation (Lepot et al. 2018), we focus on the situation where the cooling is uniform,…

Fluid Dynamics · Physics 2020-10-21 Benjamin Miquel , Vincent Bouillaut , Sebastien Aumaitre , Basile Gallet

The dependence of the heat transfer, as measured by the nondimensional Nusselt number $Nu$, on Ekman pumping for rapidly rotating Rayleigh-B\'enard convection in an infinite plane layer is examined for fluids with Prandtl number $Pr = 1$. A…

Fluid Dynamics · Physics 2017-09-13 Meredith Plumley , Keith Julien , Philippe Marti , Stephan Stellmach
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