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A new theory of coherent structure in wall turbulence is presented. The theory is the first to predict packets of hairpin vortices and other structure in turbulence, and their dynamics, based on an analysis of the Navier-Stokes equations,…

Fluid Dynamics · Physics 2013-09-04 A S Sharma , B J McKeon

Recent research has shed light on the role of coherent structures in forming layers when stably stratified turbulence is forced with horizontal shear (Lucas, Caulfield & Kerswell, J. Fluid Mech., vol. 832, 2017, pp. 409-437). Here we extend…

Fluid Dynamics · Physics 2019-05-01 Dan Lucas , C. P. Caulfield , Rich R. Kerswell

Natural convection in a cylinder with an internally slotted annulus was solved by SIMPLE algorithm, and the effects of different slotted structures on nonlinear characteristics of natural convection were investigated. The results show that…

Fluid Dynamics · Physics 2016-04-01 Chunyun Shen , Mo Yang , Yuwen Zhang , Zheng Li

Combined measurements of velocity components and temperature in a turbulent Rayleigh-B\'enard convection flow at a low Prandtl number of $\mathit{Pr}= 0.029$ and Rayleigh numbers between $10^6 \le \mathit{Ra} \le 6 \times 10^7$ are…

Fluid Dynamics · Physics 2020-02-19 Till Zürner , Felix Schindler , Tobias Vogt , Sven Eckert , Jörg Schumacher

A new mean-field theory of turbulent convection is developed. This theory predicts the convective wind instability in a shear-free turbulent convection which causes formation of large-scale semi-organized fluid motions in the form of cells…

Astrophysics · Physics 2009-11-07 T. Elperin , N. Kleeorin , I. Rogachevskii , S. Zilitinkevich

We present theory of two-dimensional turbulence excited by an external force in thin fluid films on scales larger than the film thickness. The principal feature of two-dimensional turbulence is the tendency of producing motions of larger…

Fluid Dynamics · Physics 2024-03-07 Igor V. Kolokolov , Vladimir V. Lebedev

We present results of the study of a turbulent air flow with a large scale circulation in Rayleigh-Benard rectangular convective cell with a heated bottom wall and a cooled top wall. The mean horizontal velocity of the main roll and the…

Fluid Dynamics · Physics 2015-06-18 A. Eidelman , T. Elperin , I. Gluzman , E. Golbraikh

The arrangement of brine above water across a micro porous permeable membrane is used to study high Rayleigh Number($10^{11}- 10^{10}$) high Schmidt number(650)turbulent convection. The flux shows 4/3$^{rd}$ scaling with line plume as the…

Fluid Dynamics · Physics 2010-06-09 Baburaj A. Puthenveettil , Jaywant H. Arakeri

The objective of this work is to investigate the challenges encountered in Scale-Resolving Simulations (SRS's) of turbulent wake flows driven by spatially-developing coherent structures. SRS's of practical interest are expressly intended…

Fluid Dynamics · Physics 2018-01-16 F. S. Pereira , L. Eca , G. Vaz , S. S. Girimaji

Double-diffusive convection in a horizontally infinite layer of a unit height in a large Rayleigh numbers limit is considered. From linear stability analysis it is shown, that the convection tends to have a form of travelling tall thin…

Atmospheric and Oceanic Physics · Physics 2009-11-11 S. B. Kozitskiy

In this study we report numerical results of turbulent transport of heat $Nu$ and angular momentum $\nu_{t}/\nu$ in Taylor-Couette (TC) flows subjected to a radial temperature gradient. Direct numerical simulations are performed in a TC…

Fluid Dynamics · Physics 2021-11-25 X. -Y. Leng , J. -Q. Zhong

Double-diffusive convection driven by both thermal and compositional buoyancy in a rotating spherical shell can exhibit a rather large number of behaviours often distinct from that of the single diffusive system. In order to understand how…

Fluid Dynamics · Physics 2020-04-28 Luis Silva , James F. Mather , Radostin D. Simitev

We investigate the coupling effect of buoyancy and shear based on an annular centrifugal Rayleigh-B\'enard convection (ACRBC) system in which two cylinders rotate with an angular velocity difference. Direct numerical simulations are…

Fluid Dynamics · Physics 2023-07-25 Jun Zhong , Dongpu Wang , Chao Sun

The multiscale flow structure in the solar convection zone - the coexistence of such features as the granules, mesogranules, supergranules and giant cells - has not yet been properly understood. Here, the possible role of one physical…

Solar and Stellar Astrophysics · Physics 2018-02-15 O. V. Shcheritsa , A. V. Getling , O. S. Mazhorova

A flow generator is described in which homogeneous axisymmetric turbulent air flows with varying and fully controllable degrees of anisotropy, including the much studied isotropic case, are generated by the combined agitations produced by…

Fluid Dynamics · Physics 2012-02-01 Kelken Chang

Global intermittency is observed in the stably stratified Atmospheric Boundary Layer (ABL) and corresponds to having large nonturbulent flow regions to develop in an otherwise turbulent flow. In this paper, the differences between…

Fluid Dynamics · Physics 2021-11-17 Abhishek Harikrishnan , Cedrick Ansorge , Rupert Klein , Nikki Vercauteren

Two-way coupled direct numerical simulations are used to investigate the effects of inertial particles on self-sustained, turbulent coherent structures (i.e. the so-called the regeneration cycle) in plane Couette flow at low Reynolds number…

Fluid Dynamics · Physics 2019-01-30 Guiquan Wang , David Richter

Horizontally extended turbulent convection, termed mesoscale convection in natural systems, remains a challenge to investigate in both experiments and simulations. This is particularly so for very low molecular Prandtl numbers as in stellar…

Fluid Dynamics · Physics 2022-09-09 Ambrish Pandey , Dmitry Krasnov , Katepalli R. Sreenivasan , Jörg Schumacher

We investigate properties of turbulence and turbulent transport of non-inertial particles described in terms of turbulent thermal diffusion in strongly inhomogeneous and anisotropic convection forced by two similar turbulence generators…

Fluid Dynamics · Physics 2025-12-17 E. Zarbib , E. Elmakies , O. Shildkrot , N. Kleeorin , A. Levy , I. Rogachevskii

Due to large scale flow inhomogeneities and the effects of temperature, turbulence small-scale structure in thermal convection is still an active field of investigation, especially considering sophisticated Lagrangian statistics. Here we…