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The structure and the dynamics of homogeneous turbulence are modified by the presence of body forces such that the Coriolis or the buoyancy forces, which may render a wide range of turbulence scales anisotropic. The corresponding…

Fluid Dynamics · Physics 2012-02-10 Fabien S. Godeferd

Turbulent fluid flows exhibit a complex small-scale structure with frequently occurring extreme velocity gradients. Particles probing such swirling and straining regions respond with an intricate shape-dependent orientational dynamics,…

Fluid Dynamics · Physics 2020-11-30 Leonhard A. Leppin , Michael Wilczek

This two-part review summarizes interstellar turbulence and its implications. The first part begins with diagnostics and energy sources. Turbulence theory is considered in detail, including the basic fluid equations, solenoidal and…

Astrophysics · Physics 2008-11-26 Bruce G. Elmegreen , John Scalo

We investigate astrophysical contributions to the statistical uncertainty of precision radial velocity measurements of stellar spectra. We analytically determine the uncertainty in centroiding isolated spectral lines broadened by Gaussian,…

Solar and Stellar Astrophysics · Physics 2015-12-23 Thomas G. Beatty , B. Scott Gaudi

MHD Turbulence is a critical component of the current paradigms of star formation, particle transport, magnetic reconnection and evolution of the ISM. Progress on this difficult subject is made via numerical simulations and observational…

Astrophysics of Galaxies · Physics 2011-05-06 Blakesley Burkhart , Alex Lazarian

We investigate the statistics of orientation of small, neutrally buoyant, spherical tracers whose center of mass is displaced from the geometrical center. If appropriate-sized particles are considered, a linear relation can be derived…

Fluid Dynamics · Physics 2013-05-14 Guido Boffetta , Massimo Cencini , Filippo De Lillo , Francesco Santamaria

Using experimental longitudinal and transverse velocities data for very high Reynolds number turbulence, we study both anisotropy and asymmetry of turbulence. These both seem to be related to small scale turbulent structures, and to…

Atmospheric and Oceanic Physics · Physics 2007-05-23 S. I. Vainshtien

We study compressible MHD turbulence, which holds key to many astrophysical processes, including star formation and cosmic ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid we use wavelet…

Astrophysics of Galaxies · Physics 2015-05-18 Grzegorz Kowal , Alex Lazarian

Theoretical approaches to low-frequency magnetized turbulence in collisionless and weakly collisional astrophysical plasmas are reviewed. The proper starting point for an analytical description of these plasmas is kinetic theory, not fluid…

Astrophysics · Physics 2009-11-11 A. A. Schekochihin , S. C. Cowley , W. Dorland

The numerical experiments of turbulence conducted by Gotoh et al. are analyzed precisely with the help of the formulae for the scaling exponents of velocity structure function and for the probability density function (PDF) of velocity…

Statistical Mechanics · Physics 2009-11-07 T. Arimitsu , N. Arimitsu

We discuss a new technique for studying astrophysical turbulence that utilizes the statistics of Doppler-broadened spectral lines. The technique relates the power Velocity Coordinate Spectrum (VCS), i.e. the spectrum of fluctuations…

Astrophysics · Physics 2009-11-11 A. Lazarian , D. Pogosyan

MHD Turbulence is a critical component of the current paradigms of star formation, particle transport, magnetic reconnection and evolution of the ISM, to name just a few. Progress on this difficult subject is made via numerical simulations…

Astrophysics of Galaxies · Physics 2015-05-27 Blakesley Burkhart , Alex Lazarian

This paper is devoted to a statistical analysis of the velocity fluctuations arising from a random distribution of point vortices in two-dimensional turbulence. Exact results are derived for the correlations in the velocities occurring at…

Statistical Mechanics · Physics 2009-10-31 Pierre-Henri Chavanis , Clément Sire

The recent development of the Velocity Gradient Technique allows observers to map magnetic field orientations and magnetization using the direction of velocity gradients. Aside from the directions, amplitudes of velocity gradients also…

Astrophysics of Galaxies · Physics 2020-05-15 Ka Ho Yuen , A. Lazarian

Understanding turbulence within the Intracluster Medium (ICM) of galaxy clusters is pivotal for comprehending their evolution and dynamics. Employing 3D magnetohydrodynamic (MHD) simulations of galaxy cluster mergers, we examine the…

Astrophysics of Galaxies · Physics 2025-07-30 Yue Hu , Alex Lazarian , G. Brunetti , John A. ZuHone

Turbulence is ubiquitous in the insterstellar medium and plays a major role in several processes such as the formation of dense structures and stars, the stability of molecular clouds, the amplification of magnetic fields, and the…

Astrophysics of Galaxies · Physics 2015-06-19 D. Falceta-Goncalves , G. Kowal , E. Falgarone , A. C. -L. Chian

Some pressure and pressure-velocity correlation in a direct numerical simulations of a three-dimensional turbulent flow at moderate Reynolds numbers have been analyzed. We have identified a set of pressure-velocity correlations which…

Chaotic Dynamics · Physics 2009-10-31 L. Biferale , P. Gualtieri , F. Toschi

Recent development of the velocity gradient technique shows the {\toreferee capability} of the technique in the way of tracing magnetic fields morphology in diffuse interstellar gas and molecular clouds. In this paper, we perform the…

Astrophysics of Galaxies · Physics 2023-02-01 Ka Wai Ho , Alex Lazarian

The statistical mechanical description of two-dimensional inviscid fluid turbulence is reconsidered. Using this description, we make predictions about turbulent flow in a rapidly rotating laboratory annulus. Measurements on the continuously…

Soft Condensed Matter · Physics 2009-11-11 Sunghwan Jung , P. J. Morrison , Harry L. Swinney

To study subregions of a turbulence velocity field, a long record of velocity data of grid turbulence is divided into smaller segments. For each segment, we calculate statistics such as the mean rate of energy dissipation and the mean…

Fluid Dynamics · Physics 2009-11-13 H. Mouri , A. Hori , M. Takaoka