Related papers: Turbulent stresses as a function of shear rate in …
Accretion disks are likely threaded by external vertical magnetic flux, which enhances the level of turbulence via the magnetorotational instability (MRI). Using shearing-box simulations, we find that such external magnetic flux also…
A three-dimensional direct numerical simulation (3D DNS) is performed to describe the turbulent flow in an enclosed rotor-stator cavity characterized by a large aspect ratio $G=(b-a)/h=18.32$ and a small radius ratio $a/b=0.15$ ($a$ and $b$…
We investigate the analogy between circumstellar disks and the Taylor-Couette flow. Using the Reynolds similarity principle, the analogy results in a number of parameter-free predictions about stability of the disks, and their turbulent…
Non-linear evolution of the parametric instability of inertial waves inherent to eccentric discs is studied by way of a new local numerical model. Mode coupling of tidal deformation with the disc eccentricity is known to produce…
Many dynamical interactions can induce eccentricities in astrophysical accretion disks. Disk eccentricities in turn seed a variety of instabilities, even in ideal hydrodynamics. We use 3D nonlinear simulations and 2+1D linear calculations…
We study the properties of the turbulence driven by the magnetorotational instability (MRI) in a stratified shearing box with outflow boundary conditions and an equation of state determined by self-consistent dissipation and radiation…
The magneto-rotational instability (MRI) - which is due to an interplay between a sheared background and the magnetic field - is commonly considered a key ingredient for developing and sustaining turbulence in the outer envelope of binary…
The magnetorotational instability (MRI) is the leading candidate for driving turbulence, angular momentum transport, and accretion in astrophysical disks. I consider the linear theory of the MRI in a thin, equatorial disk in the Kerr…
We study the dependence of turbulent transport coefficients, such as the components of the $\alpha$ tensor ($\alpha_{ij}$) and the turbulent magnetic diffusivity tensor ($\eta_{ij}$), on shear and magnetic Reynolds number in the presence of…
Aims: To determine alpha effect and turbulent magnetic diffusivity for mean magnetic fields with profiles of different length scale from simulations of isotropic turbulence, and to relate these results to nonlocal formulations in which…
Enhanced angular momentum transfer through the boundary layer near the surface of weakly magnetised accreting star is required in order to explain the observed accretion timescales in low-mass X-ray binaries, cataclysmic variables or young…
(Abridged) We report results of three dimensional MHD simulations of global accretion disks threaded with weak vertical magnetic fields. We perform the simulations in the spherical coordinates with different temperature profiles and…
Data available in literature from direct numerical simulations of two-dimensional turbulent channels by Lee & Moser (2015), Bernardini et al. (2014), Yamamoto and Tsuji (2018) and Orlandi et al. (2015) in a large range of Reynolds number…
The causal relevance of local flow conditions in wall-bounded turbulence is analysed using ensembles of interventional experiments in which the effect of perturbing the flow within a small cell is monitored at some future time. When this is…
The stresses produced by magnetorotational turbulence can provide effective angular momentum transport in accretion disks. However, questions remain about the ability of simulated disks to reproduce observationally inferred…
Grid-based magnetohydrodynamic (MHD) simulations have proven invaluable for the study of astrophysical accretion disks. However, the fact that angular momentum transport in disks is mediated by MHD turbulence (with structure down to very…
The pressure strain correlation plays a critical role in the Reynolds stress transport modelling. Accurate modelling of the pressure strain correlation leads to proper prediction of turbulence stresses and subsequently the other terms of…
We present the results of a series of radiation-MHD simulations of a local patch of an accretion disk, with fixed vertical gravity profile but with different surface mass densities and a broad range of radiation to gas pressure ratios. Each…
This paper reports on 3D numerical simulations of dynamics and thermodynamics in the diffuse ISM. Our models are local, account for sheared galactic rotation, magnetic fields, and realistic cooling, and resolve scales ~1-200 pc. This…
We discuss the possibility that astrophysical accretion disks are dynamically unstable to non-axisymmetric disturbances with characteristic scales much smaller than the vertical scale height. The instability is studied using three methods:…