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We investigate the phenomenon of turbulent thermal diffusion of inertial solid particles in laboratory experiments with convective turbulence forced by one or two oscillating grids in the air. Turbulent thermal diffusion causes a…

Fluid Dynamics · Physics 2026-05-26 E. Elmakies , O. Shildkrot , N. Kleeorin , A. Levy , I. Rogachevskii

The ability of streamwise-travelling waves of spanwise velocity to reduce the turbulent skin friction drag is assessed in the compressible regime. Direct numerical simulations are carried out to compare drag reduction in subsonic, transonic…

We suggest certain effects, caused by interaction between rotation and gravitation with turbulence structure, for the cooling/heating of dispersed phase of non-isothermal particles in rotating turbulent fluid flows. These effects are…

Fluid Dynamics · Physics 2015-04-07 R. V. R. Pandya , P. Stansell

There is a clear distinction between simple laminar and complex turbulent fluids. But in some cases, as for the nocturnal planetary boundary layer, a stable and well-ordered flow can develop intense and sporadic bursts of turbulent activity…

Fluid Dynamics · Physics 2015-06-17 C. Rorai , P. D. Mininni , A. Pouquet

Turbulence, left unforced, decays and invades the surrounding quiescent fluid. Though ubiquitous, this simple phenomenon has proven hard to capture within a simple and general framework. Experiments in conventional turbulent flow chambers…

Fluid Dynamics · Physics 2025-06-30 Takumi Matsuzawa , Minhui Zhu , Nigel Goldenfeld , William T. M. Irvine

Cold clouds embedded in warm media are very common objects in astrophysics. Their disruption timescale depends strongly on the dynamical configuration. We discuss the evolution of an initially homogeneous cold cloud embedded in warm…

Astrophysics · Physics 2009-11-11 F. Heitsch , A. D. Slyz , J. E. G. Devriendt , A. Burkert

The topic of turbulent transport in a stellar radiative zone is vast and poorly understood. Many physical processes can potentially drive turbulence in stellar radiative zone but the limited observational constraints and the uncertainties…

Solar and Stellar Astrophysics · Physics 2019-11-19 F. Lignières

In a companion paper, we develop a theory for the evolution of stellar wind driven bubbles in dense, turbulent clouds. This theory proposes that turbulent mixing at a fractal bubble-shell interface leads to highly efficient cooling, in…

Astrophysics of Galaxies · Physics 2021-06-30 Lachlan Lancaster , Eve C. Ostriker , Jeong-Gyu Kim , Chang-Goo Kim

The relationship between a decaying strong turbulence and kinetic instabilities in a slowly expanding plasma is investigated using two-dimensional (2-D) hybrid expanding box simulations. We impose an initial ambient magnetic field…

Rotation modulates turbulence causing columnar structuring of a turbulent flow in case of sufficiently strong rotation. This yields significant changes in the flow characteristics and dispersion properties, which makes rotational turbulence…

Chaotic Dynamics · Physics 2009-04-07 Arkadiusz K. Kuczaj , Bernard J. Geurts , Darryl D. Holm

Radiative shock waves show a strong cooling instability at temperatures above approximately 2 times 10^5 K. We numerically investigate this instability by simulating different astronomical objects in which colliding flows play an…

Astrophysics · Physics 2008-02-03 Rolf Walder , Doris Folini

We studied experimentally the effect of turbulent thermal diffusion in a multi-fan turbulence generator which produces a nearly homogeneous and isotropic flow with a small mean velocity. Using Particle Image Velocimetry and Image Processing…

Fluid Dynamics · Physics 2009-11-11 A. Eidelman , T. Elperin , N. Kleeorin , I. Rogachevskii , I. Sapir-Katiraie

The effect of damping in the wave turbulence regime for thin vibrating plates is studied. An experimental method, allowing measurements of dissipation in the system at all scales, is first introduced. Practical experimental devices for…

Abundant observational evidence indicates that the cooling time t_cool of the hot ambient medium pervading a massive galaxy does not drop much below 10 times the freefall time t_ff at any radius. Theoretical models have accounted for this…

Astrophysics of Galaxies · Physics 2018-12-05 G. M. Voit

Turbulent properties of the quiet Sun represent the basic state of surface conditions, and a background for various processes of solar activity. Therefore understanding of properties and dynamics of this `basic' state is important for…

Solar and Stellar Astrophysics · Physics 2012-06-27 I. N. Kitiashvili , V. I. Abramenko , P. R. Goode , A. G. Kosovichev , S. K. Lele , N. N. Mansour , A. A. Wray , V. B. Yurchyshyn

Turbulent motions due to flux-driven thermal convection is investigated by numerical simulations and stochastic modelling. Tilting of convection cells leads to the formation of sheared flows and quasi-periodic relaxation oscillations for…

Fluid Dynamics · Physics 2020-08-26 G. Decristoforo , A. Theodorsen , O. E. Garcia

We investigate the role of thermal instability, arising from radiative cooling of an optically thin, dusty plasma, by linear stability analysis. The corresponding isobaric stability condition for condensation mode is found to be modified…

Plasma Physics · Physics 2007-05-23 Madhurjya P. Bora

Energy loss through optically thin radiative cooling plays an important part in the evolution of astrophysical gas dynamics and should therefore be considered a necessary element in any numerical simulation. Although the addition of this…

Instrumentation and Methods for Astrophysics · Physics 2010-11-12 Allard Jan van Marle , Rony Keppens

In astrophysics, turbulent diffusion is often used in place of microphysical diffusion to avoid resolving the small scales. However, we expect this approach to break down when time and length scales of the turbulence become comparable with…

Solar and Stellar Astrophysics · Physics 2014-09-05 M. S. Väisälä , A. Brandenburg , Dhrubaditya Mitra , P. J. Käpylä , M. J. Mantere

Compressibility effects in a turbulent transport of temperature field are investigated applying the quasi-linear approach for small P\'eclet numbers and the spectral $\tau$ approach for large P\'eclet numbers. Compressibility of a fluid…

Fluid Dynamics · Physics 2021-01-27 I. Rogachevskii , N. Kleeorin