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Related papers: Turbulent transport and entrainment in jets and pl…

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Accurate models of turbulent buoyant flows are essential for the design of nuclear reactors thermal hydraulics and passive safety systems. However, available models fail to fully capture the physics of turbulent mixing when buoyancy becomes…

Fluid Dynamics · Physics 2024-02-27 Valentina Valori , Sunming Qin , Victor Petrov , Annalisa Manera

The breakup of a fluid jet into droplets has long fascinated natural scientists, with early research dating back to the 19th century. Infinitesimal perturbations to a jet grow because of surface tension, which eventually leads to breakup of…

Fluid Dynamics · Physics 2022-09-07 Takuji Ishikawa , Thanh-Nghi Dang , Eric Lauga

We propose an experimental study on the gravitational settling velocity of dense, sub-Kolmogorov inertial particles under different background turbulent flows. We report Phase Doppler Particle Analyzer measurements in a low-speed wind…

Fluid Dynamics · Physics 2022-07-18 Amélie Ferran , Nathanaël Machicoane , Alberto Aliseda , Martín Obligado

Horizontal Convection (HC) at large Rayleigh and Prandtl numbers, is studied experimentally in a regime up to seven orders of magnitude larger in terms of Rayleigh numbers than previously achieved. To reach Rayleigh up to $10^{17}$, the…

Fluid Dynamics · Physics 2020-05-01 Pierre-Yves Passaggia , Nadia F. Cohen , Alberto Scotti , Brian L. White

The relative dispersion of pairs of inertial particles in incompressible, homogeneous, and isotropic turbulence is studied by means of direct numerical simulations at two values of the Taylor-scale Reynolds number $Re_{\lambda} \sim 200$…

Fluid Dynamics · Physics 2015-05-13 J. Bec , L. Biferale , A. S. Lanotte , A. Scagliarini , F. Toschi

Turbulent stripe, which would occur in turbulent channel flows at transitional Reynolds numbers, was studied experimentally by flow visualization using reflective flake particles. In a range of bulk mean Reynolds number Re = 1700-2000, the…

Fluid Dynamics · Physics 2014-09-18 Takahiro Tsukahara , Yasuo Kawaguchi , Hiroshi Kawamura

The stability problem of MHD Taylor-Couette flows with toroidal magnetic fields is considered in dependence on the magnetic Prandtl number. Only the most uniform (but not current-free) field with B\_in = B\_out has been considered. For high…

Astrophysics · Physics 2008-09-22 M. Gellert , G. Ruediger

We study entrainment in dry thermals in neutrally and unstably stratified ambients, and moist thermals in dry-neutrally stratified ambients using direct numerical simulations (DNS). We find, in agreement with results of Lecoanet and…

Fluid Dynamics · Physics 2022-05-19 G. R. Vybhav , S. Ravichandran

Heat transfer by large deformable drops in a turbulent flow is a complex and rich in physics system, in which drops deformation, breakage and coalescence influence the transport of heat. We study this problem coupling direct numerical…

Fluid Dynamics · Physics 2023-09-26 Francesca Mangani , Alessio Roccon , Francesco Zonta , Alfredo Soldati

Astrophysical jets are often observed as bent or curved structures. We also know that the different jet sources may be binary in nature, which may lead to a regular, periodic motion of the jet nozzle, an orbital motion or precession. Here,…

High Energy Astrophysical Phenomena · Physics 2022-07-20 Christian Fendt , Melis Yardimci

The transport of charged energetic particles in the presence of strong intermittent heliospheric turbulence is computationally analyzed based on known properties of the interplanetary magnetic field and solar wind plasma at 1 Astronomical…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Fathallah Alouani-Bibi , Jakobus A. le Roux

One route to improved predictive modeling of magnetically confined fusion reactors is to couple transport solvers with direct numerical simulations (DNS) of turbulence, rather than with surrogate models. An additional challenge presented by…

Plasma Physics · Physics 2018-07-16 Jeffrey B. Parker , Lynda L. LoDestro , Alejandro Campos

We study the dynamics of line plumes on the bottom plate in turbulent convection over six decades of Rayleigh number $(10^5<Ra_w<10^{11})$ and two decades of Prandtl number $(0.7<Pr<600)$. We qualitatively identify the main dynamics as…

Fluid Dynamics · Physics 2015-06-16 G. S. Gunasegarane , Baburaj A. Puthenveettil

We have performed direct numerical simulation of the turbulent flow of a polymer solution in a square duct, with the FENE-P model used to simulate the presence of polymers. First, a simulation at a fixed moderate Reynolds number is…

Well-resolved direct numerical simulations (DNSs) have been performed of the flow in a smooth circular pipe of radius $R$ and axial length $10\pi R$ at friction Reynolds numbers up to $Re_\tau=5200$. Various turbulence statistics are…

Fluid Dynamics · Physics 2023-02-15 Jie Yao , Saleh Rezaeiravesh , Philipp Schlatter , Fazle Hussain

We report the statistical properties of temperature and thermal energy dissipation rate in low-Prandtl number turbulent Rayleigh-B\'enard convection. High resolution two-dimensional direct numerical simulations were carried out for the…

Fluid Dynamics · Physics 2019-12-12 Ao Xu , Le Shi , Heng-Dong Xi

This paper is a detailed report on a programme of simulations used to settle a long-standing issue in the dynamo theory and demonstrate that the fluctuation dynamo exists in the limit of large magnetic Reynolds number Rm>>1 and small…

This study investigates the spatial distribution of inertial particles in turbulent Taylor-Couette flow. Direct numerical simulations are performed using a one-way coupled Eulerian-Lagrangian approach, with a fixed inner wall Reynolds…

Fluid Dynamics · Physics 2024-02-28 Hao Jiang , Zhi-ming Lu , Bo-fu Wang , Xiao-hui Meng , Jie Shen , Kai Leong Chong

Recent growing interest in using machine learning for turbulence modelling has led to many proposed data-driven turbulence models in the literature. However, most of these models have not been developed with overcoming non-unique mapping…

Fluid Dynamics · Physics 2024-08-20 Anthony Man , Mohammad Jadidi , Amir Keshmiri , Hujun Yin , Yasser Mahmoudi

Knowledge of turbulent flows over non-flat surfaces is of major practical interest in diverse applications. Significant work continues to be reported in the roughness regime at high Reynolds numbers where the cumulative effect of surface…

Fluid Dynamics · Physics 2019-11-27 Balaji Jayaraman , Saadbin Khan