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Related papers: Mixing in modulated turbulence. Analytical results

200 papers

In this paper we explore the relationship between protostellar outflows and turbulence in molecular clouds. Using 3-D numerical simulations we focus on the hydrodynamics of multiple outflows interacting within a parsec scale volume. We…

The effect of electrostatic microturbulence on fast particles rapidly decreases at high energy, but can be significant at moderate energy. Previous studies found that, in addition to changes in the energetic particle density, this results…

Plasma Physics · Physics 2018-12-26 George J. Wilkie

This paper presents a comprehensive description of the relative effect of optical underwater turbulence in combination with absorption and scattering. Turbulence induced scattering is shown to cause and increase both spatial and temporal…

Signal Processing · Electrical Eng. & Systems 2021-01-15 Callum T. Geldard , John Thompson , Wasiu O. Popoola

We investigate the mixing properties of scalars stirred by spatially smooth, divergence-free flows and maintained by a steady source-sink distribution. We focus on the spatial variation of the scalar field, described by the {\it dissipation…

Fluid Dynamics · Physics 2015-05-27 Alexandros Alexakis , Alexandra Tzella

A popular method of forcing the fluid in Direct Numerical Simulations of turbulence is to take the body force proportional to the projection of the velocity of the fluid onto its lowest Fourier modes, while keeping the injected external…

Fluid Dynamics · Physics 2007-05-23 Charles R. Doering , Nikola P. Petrov

The mixing efficiency of a flow advecting a passive scalar sustained by steady sources and sinks is naturally defined in terms of the suppression of bulk scalar variance in the presence of stirring, relative to the variance in the absence…

Fluid Dynamics · Physics 2011-05-03 Tiffany A. Shaw , Jean-Luc Thiffeault , Charles R. Doering

Feedback from protostellar outflows can influence the nature of turbulence in star forming regions even if they are not the primary source of velocity dispersion for all scales of molecular clouds. For the rate and power expected in star…

Solar and Stellar Astrophysics · Physics 2015-05-18 Jonathan J. Carroll , Adam Frank , Eric G Blackman

How locally injected turbulence, spreads in space is investigated with direct numerical simulations. We consider a turbulent flow in a long channel generated by a forcing that is localised in space. The forcing is such that it does not…

Fluid Dynamics · Physics 2023-07-18 Alexandros Alexakis

Under action of free-stream turbulence (FST), elongated streamwise streaky structures are generated inside the boundary layer, and their amplitude and wavelength are crucial for the transition onset. While turbulence intensity is strongly…

The effects of turbulent dynamic range on scalar mixing in stably stratified turbulence are investigated by an adaptation of the theoretical passive scalar modelling arguments of Beguier et al. (1978) and demonstrated statistically using…

Fluid Dynamics · Physics 2022-04-05 G. D. Portwood , S. M. de Bruyn Kops , C. P. Caulfield

Various approaches to estimate turbulent transport coefficients from numerical simulations of hydromagnetic turbulence are discussed. A quantitative comparison between the averaged magnetic field obtained from a specific three-dimensional…

Astrophysics · Physics 2009-11-07 Axel Brandenburg , Dmitry Sokoloff

In this study, we revisit the spectral transfer model for the turbulent intensity in the passive scalar transport (under large-scale anisotropic forcing), and a subsequent modification to the scaling of scalar variance cascade is presented.…

Fluid Dynamics · Physics 2021-11-15 Ali Akhavan-Safaei , Mohsen Zayernouri

Radiation transport plays important roles in stellar atmospheres, but the effects of turbulence are being obscured by other effects such as stratification. Using radiative hydrodynamic simulations of forced turbulence, we determine the…

Fluid Dynamics · Physics 2021-09-29 Axel Brandenburg , Upasana Das

A variety of studies of magnetised plasma turbulence invoke theories for the advection of a passive scalar by turbulent fluctuations. Examples include modelling the electron density fluctuations in the interstellar medium, understanding the…

Plasma Physics · Physics 2015-06-23 Joanne Mason , Stanislav Boldyrev , Fausto Cattaneo , Jean Carlos Perez

An analysis of instability dynamics in a stochastic magnetic field is presented for the tractable case of the resistive interchange. Externally prescribed static magnetic perturbations convert the eigenmode problem to a stochastic…

Plasma Physics · Physics 2023-06-14 Mingyun Cao , P. H. Diamond

We investigate the effect that the turbulent mixing strength parameter $\alpha_{\rm{turb}}$ plays on near-infrared polarimetric and sub-millimetre interferometric imaging observations of transitional discs (TDs) with a gap carved by a…

Solar and Stellar Astrophysics · Physics 2016-04-01 M. de Juan Ovelar , P. Pinilla , M. Min , C. Dominik , T. Birnstiel

To investigate the attenuation of turbulence in a periodic cube due to the addition of spherical solid particles, we conduct direct numerical simulations using an immersed boundary method with resolving flow around each particle. Numerical…

Fluid Dynamics · Physics 2022-10-19 Sunao Oka , Susumu Goto

In continuation of previous work, numerical results are presented, concerning relativistically counter-streaming plasmas. Here, the relativistic mixed mode instability evolves through, and beyond, the linear saturation -- well into the…

Plasma Physics · Physics 2008-11-26 Jacob Trier Frederiksen , Mark Eric Dieckmann

Periodic forcing of flow in compressible porous media is an important driver for solute dispersion and mixing in geological and engineered porous media subject for example to tides, pumping and recharge cycles, or fluid injection and…

Fluid Dynamics · Physics 2025-06-17 Satoshi Tajima , Marco Dentz

The evolution of scalar fields transported by turbulent flow is characterized by the presence of fronts, which rule the small-scale statistics of scalar fluctuations. With the aid of numerical simulations, it is shown that: isotropy is not…

Chaotic Dynamics · Physics 2009-10-31 A. Celani , A. Lanotte , A. Mazzino , M. Vergassola