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Related papers: Nonhelical turbulent dynamos: shocks and shear

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The transitional and well-developed regimes of turbulent shear flows exhibit a variety of remarkable scaling laws that are only now beginning to be systematically studied and understood. In the first part of this article, we summarize…

Fluid Dynamics · Physics 2017-01-04 Nigel Goldenfeld , Hong-Yan Shih

Near-wall turbulent velocities in turbulent channel flows are decomposed into small-scale and large-scale components at $y^+<100$ by improving the predictive inner-outer model of Baars et al. [Phys. Rev. Fluids 1, 054406 (2016)], where…

Fluid Dynamics · Physics 2021-04-16 Limin Wang , Ruifeng Hu , Xiaojing Zheng

Using direct numerical simulations, we verify that "flow IV" of Roberts (1972) exhibits dynamo action dominated by horizontally averaged large-scale magnetic field. With the test-field method we compute the turbulent magnetic diffusivity…

Solar and Stellar Astrophysics · Physics 2013-08-09 Ebru Devlen , Axel Brandenburg , Dhrubaditya Mitra

According to the kinematic theory of nonhelical dynamo action the magnetic energy spectrum increases with wavenumber and peaks at the resistive cutoff wavenumber. It has previously been argued that even in the dynamical case the magnetic…

Astrophysics · Physics 2009-11-10 Nils Erland L. Haugen , Axel Brandenburg , Wolfgang Dobler

We investigate high-Reynolds number turbulence in dilute polymer solutions. We show the existence of a critical value of the Reynolds number which separates two different regimes. In the first regime, below the transition, the influence of…

Chaotic Dynamics · Physics 2009-11-07 E. Balkovsky , A. Fouxon , V. Lebedev

The supernova-driven interstellar medium in star-forming galaxies has Reynolds numbers of the order of $10^{6}$ or even larger. We study, by means of adaptive mesh refinement hydro- and magnetohydrodynamical simulations that cover the full…

Astrophysics · Physics 2007-05-23 M. A. de Avillez , D. Breitschwerdt

The nonequilibrium dissipation behaviour discovered for decaying fractal square grid-generated turbulence is experimentally investigated using hot-wire anemometry in a wind tunnel. The previous results are consolidated and benchmarked with…

Fluid Dynamics · Physics 2013-07-25 Pedro C. Valente

The feasibility of a mean-field dynamo in nonhelical turbulence with superimposed linear shear is studied numerically in elongated shearing boxes. Exponential growth of magnetic field at scales much larger than the outer scale of the…

The conventional theory of small-scale magnetic field generation in a turbulent flow considers time-reversible random flows. However, real turbulent flows are known to be time irreversible: the presence of energy cascade is an intrinsic…

Fluid Dynamics · Physics 2023-12-20 A. V. Kopyev , A. S. Il'yn , V. A. Sirota , K. P. Zybin

Rational large Reynolds number matched asymptotic expansions of three-dimensional nonlinear magneto-hydrodynamic (MHD) states are concerned. The nonlinear MHD states, assumed to be predominantly driven by a unidirectional shear, can be…

Fluid Dynamics · Physics 2019-05-01 Kengo Deguchi

Direct numerical simulations (DNS) of fully-developed turbulent channel flows for very low Reynolds numbers have been performed with a larger computational box sizes than those of existing DNS. The friction Reynolds number was decreased…

Fluid Dynamics · Physics 2014-09-17 Takahiro Tsukahara , Yohji Seki , Hiroshi Kawamura , Daisuke Tochio

The transition to intermittent mean--field dynamos is studied using numerical simulations of isotropic magnetohydrodynamic turbulence driven by a helical flow. The low-Prandtl number regime is investigated by keeping the kinematic viscosity…

Solar and Stellar Astrophysics · Physics 2015-05-13 Erico L. Rempel , Michael R. E. Proctor , Abraham C. -L. Chian

It is shown, using results of direct numerical simulations, that the spontaneous breaking of local reflectional symmetry (and corresponding localized kinetic and magnetic helicities) can dominate chaotic dynamics of the small-scale MHD…

Fluid Dynamics · Physics 2022-09-14 A. Bershadskii

The inverse transfer of magnetic helicity is investigated through direct numerical simulations of large-scale-mechanically-driven turbulent flows in the isothermal ideal magnetohydrodynamics (MHD) framework. The mechanical forcing is either…

Plasma Physics · Physics 2021-03-15 Jean-Mathieu Teissier , Wolf-Christian Müller

We introduce a novel toy model for shear flows, exploiting the spatial intermittency and the scale separation between large-scale flows and small-scale structures. The model is highly sparse, focusing exclusively on the most intense…

Fluid Dynamics · Physics 2025-03-18 Wandrille Ruffenach , Lucas Fery , Bérengère Dubrulle

This manuscript has been accepted for publication in Physical Review Fluids, see https://journals.aps.org/prfluids/accepted/d5074S28J6b11905012b7cb06505e8f2149dd5f20. This work investigates the mechanisms that underlie transitions to…

Fluid Dynamics · Physics 2020-12-24 Christopher J. Camobreco , Alban Pothérat , Gregory J. Sheard

In this work we present a simple qualitative model to describe shear rheological behavior of the twist-bend nematic liquid crystals. We find that at relatively low shear rate the effective viscosity decreases with the shear rate manifesting…

Soft Condensed Matter · Physics 2022-10-26 E. I. Kats

High Reynolds number isotropic magneto-hydro-dynamic turbulence in the presence of large scale magnetic fields is investigated as a function of the magnetic field strength. For a variety of flow configurations the energy dissipation rate…

Fluid Dynamics · Physics 2012-09-20 Alexandros Alexakis

It is shown that nonlocal interactions determine energy spectrum in isotropic turbulence at small Reynolds numbers. It is also shown that for moderate Reynolds numbers the bottleneck effect is determined by the same nonlocal interactions.…

Chaotic Dynamics · Physics 2008-11-07 A. Bershadskii

We use shear reversal simulations to explore the rheology of dense, non-Brownian suspensions, resolving lubrication forces between neighbouring particles and modelling particle surface contacts. The transient stress response to an abrupt…

Soft Condensed Matter · Physics 2016-01-13 Christopher Ness , Jin Sun
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