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Direct numerical simulations are performed of turbulent forced convection in a half channel flow with wall oscillating either as a spanwise plane oscillation or to generate a streamwise travelling wave. The friction Reynolds number is fixed…

Fluid Dynamics · Physics 2025-05-14 Amirreza Rouhi , Marcus Hultmark , Alexander J. Smits

In turbulent thermal convection in cylindrical samples of aspect ratio \Gamma = D/L (D is the diameter and L the height) the Nusselt number Nu is enhanced when the sample is rotated about its vertical axis, because of the formation of Ekman…

We present a combined experimental and numerical investigation of the transition from the classical to the ultimate regime of thermal turbulence in a supergravitational centrifugal convection system. The transition is found to be robust,…

Fluid Dynamics · Physics 2025-09-19 Lei Ren , Jun Zhong , Rushi Lai , Chao Sun

We present a direct numerical simulation on the dynamics of large-scale circulation (LSC) of turbulent Rayleigh-B\'enard convection of air (Pr = 0.7) contained in a cubic cell for Rayleigh number range 2X10^6 < Ra < 10^9 . The strength and…

Fluid Dynamics · Physics 2019-09-25 V. T. Vishnu , A. K. De , P. K. Mishra

In this paper, we present results from an experimental study into turbulent Rayleigh-Benard convection forced externally by periodically modulated unidirectional rotation rates. We find that the azimuthal rotation velocity $\dot{\theta}$(t)…

Fluid Dynamics · Physics 2016-09-14 Sebastian Sterl , Hui-Min Li , Jin-Qiang Zhong

We present direct numerical simulation results of turbulent open channel flow at bulk Reynolds numbers up to 12000, coupled with (passive) scalar transport at Schmidt numbers up to 200. Care is taken to capture the very large scale motions…

Fluid Dynamics · Physics 2022-01-19 Michele Pinelli , Herlina Herlina , Jan G. Wissink , Markus Uhlmann

We numerically study the Rayleigh-B\'enard (RB) convection in two-dimensional model emulsions confined between two parallel walls at fixed temperatures. The systems under study are heterogeneous, with finite-size droplets dispersed in a…

Convection is a key transport phenomenon important in many different areas, from hydrodynamics and ocean circulation to planetary atmospheres or stellar physics. However its microscopic understanding still remains challenging. Here we…

Statistical Mechanics · Physics 2022-07-29 P. L. Garrido , P. I. Hurtado

{\bf Direct} transition from low Reynolds number "weak" Gaussian turbulence to fully developed "strong" turbulence at a critical Reynolds number $R^{tr}_{\lambda}\approx 8.91$ has recently been theoretically predicted and tested in high…

Fluid Dynamics · Physics 2019-07-01 victor Yakhot

This study investigates the effect of vibration on the flow structure transitions in thermal vibrational convection (TVC) systems, which occur when a fluid layer with a temperature gradient is excited by vibration. Direct numerical…

Fluid Dynamics · Physics 2023-03-30 Xili Guo , Jianzhao Wu , Bofu Wang , Quan Zhou , Kai Leong Chong

Planetary cores consist of liquid metals (low Prandtl number $Pr$) that convect as the core cools. Here we study nonlinear convection in a rotating (low Ekman number $Ek$) planetary core using a fully 3D direct numerical simulation. Near…

Geophysics · Physics 2017-09-06 E. J. Kaplan , N. Schaeffer , J. Vidal , P. Cardin

It is known that turbulent energy is rapidly transferred in the direction of the rotation axis in a rotating system, in comparison with the non-rotating case. In this study, this phenomenon is investigated as a problem of energy diffusion…

Fluid Dynamics · Physics 2018-12-12 Kazuhiro Inagaki , Fujihiro Hamba

We conducted direct numerical simulations (DNSs) of turbulent flow over three-dimensional sinusoidal roughness in a channel. A passive scalar is present in the flow with Prandtl number $Pr=0.7$, to study heat transfer by forced convection…

Fluid Dynamics · Physics 2019-02-20 M. MacDonald , N. Hutchins , D. Chung

We investigate the influence of the Prandtl number ($Pr$) on penetrative internally heated convection (IHC) in both non-rotating and rotating regimes using three-dimensional direct numerical simulations. By varying $Pr$ between 0.1 and 100,…

Fluid Dynamics · Physics 2026-05-14 Rodolfo Ostilla-Mónico , Ali Arslan

The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-B\'enard convection is theoretically analysed. The force and thermal balance on a single plume detached from the thermal…

Chaotic Dynamics · Physics 2009-11-10 Francisco Fontenele Araujo , S. Grossmann , D. Lohse

We numerically simulate three-dimensional Rayleigh-B\'enard convection, the flow in a fluid layer heated from below and cooled from above, with inhomogeneous temperature boundary conditions to explore two distinct regimes described in…

Fluid Dynamics · Physics 2020-10-28 Rodolfo Ostilla-Monico , Amit Amritkar

Direct numerical simulations of turbulent heat transfer in fully-developed channel flows have been performed in a range of friction Reynolds number between 60 and 180, based on the friction velocity and the channel half width $\delta$, with…

Fluid Dynamics · Physics 2014-09-18 Takahiro Tsukahara , Kaoru Iwamoto , Hiroshi Kawamura , Tetsuaki Takeda

Large-scale patterns, which are well-known from the spiral defect chaos regime of thermal convection at Rayleigh numbers $Ra < 10^4$, continue to exist in three-dimensional numerical simulations of turbulent Rayleigh-B\'{e}nard convection…

Fluid Dynamics · Physics 2016-12-30 Mohammad S. Emran , Jörg Schumacher

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

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…