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200 papers

The observed rapid onset of star formation in molecular clouds requires rapid formation of dense fragments which can collapse individually before being overtaken by global gravitationally-driven flows. Many previous investigations have…

Astrophysics · Physics 2009-11-13 F. Heitsch , L. Hartmann , A. Burkert , ;

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…

This work has the main objective to provide a detailed investigation of cosmic ray propagation in magnetohydrodynamic turbulent fields generated by forcing the fluid velocity field at large scales. It provides a derivation of the particle…

High Energy Astrophysical Phenomena · Physics 2016-03-25 Romain Cohet , Alexandre Marcowith

We analyze a set of bidirectional wave experiments in a linear wave flume of which some are conducive to integrable turbulence. In all experiments the wavemaker forcing is sinusoidal and the wave motion is recorded by seven high-resolution…

Fluid Dynamics · Physics 2022-10-11 Ivan Redor , Hervé Michallet , Nicolas Mordant , Eric Barthélemy

We report results of a three dimensional, high resolution (up to 512^3) numerical investigation of supersonic compressible magnetohydrodynamic turbulence. We consider both forced and decaying turbulence. The model parameters are appropriate…

Astrophysics · Physics 2009-10-30 James M. Stone , Eve C. Ostriker , Charles F. Gammie

The star-forming efficiency of dense gas is thought to be set within cores by outflow and radiative feedback. We use magneto-hydrodynamic simulations to investigate the relation between protostellar outflow evolution, turbulence and star…

Astrophysics of Galaxies · Physics 2017-10-04 Stella S. R. Offner , Jonah Chaban

(Abridged) We explore, by means of a large ensemble of SPH simulations, how the level of turbulence affects the collapse and fragmentation of a star-forming core. All our simulated cores have the same, except that we vary (a) the initial…

Astrophysics · Physics 2014-10-13 Simon P. Goodwin , Anthony P Whitworth , Derek Ward-Thompson

We perform particle-resolved simulations of subsonic and transonic flows past random arrays of spherical particles. The Reynolds number is held at $Re{\approx}300$ to ensure the flow remains in the continuum regime. At low volume fractions,…

Fluid Dynamics · Physics 2022-08-23 Mehdi Khalloufi , Jesse Capecelatro

The role of supersonic turbulence in structuring the interstellar medium (ISM) remains an unsettled question. Here, this problem is investigated using a newexact law of compressible isothermal hydrodynamic turbulence, which involves…

Astrophysics of Galaxies · Physics 2023-03-14 Renaud Ferrand , Sébastien Galtier , Fouad Sahraoui , Christoph Federrath

We have studied forced turbulence of compressible magnetohydrodynamic (MHD) flows through two-dimensional simulations with different numerical resolutions. First, hydrodynamic turbulence with Mach number $<M_s >_{\rm init} \equiv < v >_{\rm…

Astrophysics · Physics 2009-11-07 Hyesook Lee , Dongsu Ryu , Jongsoo Kim , T. W. Jones , Dinshaw Balsara

Understanding the dynamics of soft colloids, such as star polymers, dendrimers, and microgels, is of scientific and practical importance. It is known that the excluded volume effect plays a key role in colloidal dynamics. Here, we propose a…

Soft Condensed Matter · Physics 2019-09-17 Zhe Wang , Antonio Faraone , Panchao Yin , Lionel Porcar , Yun Liu , Changwoo Do , Kunlun Hong , Wei-Ren Chen

Large-scale galactic winds driven by stellar feedback are one phenomenon that influences the dynamical and chemical evolution of a galaxy, redistributing material throughout the circumgalatic medium. Non-thermal feedback from galactic…

High Energy Astrophysical Phenomena · Physics 2019-09-25 F. Holguin , M. Ruszkowski , A. Lazarian , R. Farber , H. -Y. K. Yang

The Schmidt-Kennicutt relation links the surface densities of gas to the star formation rate in galaxies. The physical origin of this relation, and in particular its break, i.e. the transition between an inefficient regime at low gas…

Radial tidal forces can be compressive instead of disruptive, a possibility that is frequently overlooked in high level physics courses. For example, radial tidal compression can emerge in extended stellar systems containing a smaller…

Astrophysics · Physics 2009-06-23 Marco Masi

The ionizing radiation of massive stars sculpts the surrounding neutral gas into pillar-like structures. Direct signatures of star formation through outflows and jets are observed in these structures, typically at their tips. Recent…

Astrophysics of Galaxies · Physics 2020-10-28 Shyam H. Menon , Christoph Federrath , Pamela Klaassen , Rolf Kuiper , Megan Reiter

Star formation is primarily controlled by the interplay between gravity, turbulence, and magnetic fields. However, the turbulence and magnetic fields in molecular clouds near the Galactic Center may differ substantially from spiral-arm…

(abridged) Context: Solar-like differential rotation is characterized by a rapidly rotating equator and slower poles. However, theoretical models and numerical simulations can result in a slower equator and faster poles when the rotation is…

Solar and Stellar Astrophysics · Physics 2014-10-17 P. J. Käpylä , M. J. Käpylä , A. Brandenburg

We analyze high-resolution hydrodynamics simulations of an isolated disk dwarf galaxy with an explicit model for unresolved turbulence and turbulence-based star formation prescription. We examine the characteristic values of the star…

Astrophysics of Galaxies · Physics 2024-12-11 Ava Polzin , Andrey V. Kravtsov , Vadim A. Semenov , Nickolay Y. Gnedin

Pure theory recognizes the dependence of supersonic drag coefficients on both Mach number and Reynolds number, which includes an implicit dependence of drag coefficient on air density. However, many modern approaches to computing…

Popular Physics · Physics 2015-10-27 Elya Courtney , Amy Courtney , Michael Courtney

The interstellar medium of galaxies is governed by supersonic turbulence, which likely controls the star formation rate (SFR) and the initial mass function (IMF). Interstellar turbulence is non-universal, with a wide range of Mach numbers,…

Astrophysics of Galaxies · Physics 2015-03-13 Christoph Federrath , Supratik Banerjee