Related papers: Alpha-viscosity effects in slender tori
A significant fraction of the envelope of low- and intermediate-mass stars is unstable to convection, leading to sub-surface turbulent motion. Here, we consider and include the effects of turbulence pressure in our stellar evolution…
Roughness and orientational order in thin films of anisotropic particles are investigated using kinetic Monte Carlo simulations on a cubic lattice. Anisotropic next-neighbor interactions between the lattice particles were chosen to mimic…
We study the large-time behavior of finite-energy weak solutions for the Vlasov-Navier-Stokes equations in a two-dimensional torus. We focus first on the homogeneous case where the ambient (incompressible and viscous) fluid carrying the…
We study the rotational dynamics of {\it inertial} disks and rods in three-dimensional, homogeneous isotropic turbulence. In particular, we show how the alignment and the decorrelation time-scales of such spheroids depend, critically, on…
Many natural and engineering systems involve the mixing of two fluid streams, in which the effects of density and viscosity gradients play important roles in determining flow stability. We perform linear stability calculations for a jet…
We are carrying out a programme of non-linear time-dependent numerical calculations to study the evolution of the thermal instability driven by radiation pressure in transonic accretion discs around black holes. In our previous studies we…
Turbulent convection is thought to act as an effective viscosity ($\nu_E$) in damping tidal flows in stars and giant planets. However, the efficiency of this mechanism has long been debated, particularly in the regime of fast tides, when…
Using fully-resolved simulations, we investigate the torque experienced by a finite-length circular cylinder rotating steadily perpendicularly to its symmetry axis. The aspect ratio $\chi$, i.e. the ratio of the length of the cylinder to…
We consider vertical heat transport in Keplerian accretion disks, including the effects of radiation, convection, and turbulent mixing driven by the Balbus-Hawley instability, in astronomical systems ranging from dwarf novae (DNe), and soft…
We study the equations obtained from linearizing the compressible Navier-Stokes equations around a steady-state profile with a heavier fluid lying above a lighter fluid along a planar interface, i.e. a Rayleigh-Taylor instability. We…
Laminar-turbulent transition on a rotating wind turbine blade at a chord Reynolds number of $1 \times 10^5$ and varying angles of attack ($AoA$) is studied with direct numerical simulations and linear stability theory. The rotation effects…
The goal of this paper is to describe in mathematical terms the effect on the ocean circulation of a random stationary wind stress at the surface of the ocean. In order to avoid singular behaviour, non-resonance hypotheses are introduced,…
The origin of hydrodynamic turbulence in rotating shear flow is a long standing puzzle. Resolving it is especially important in astrophysics when the flow angular momentum profile is Keplerian which forms an accretion disk having negligible…
In this paper we study a well-known three--dimensional turbulence model, the filtered Clark model, or Clark-alpha model. This is Large Eddy Simulation (LES) tensor-diffusivity model of turbulent flows with an additional spatial filter of…
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…
We demonstrate that the compact, thick disc formed in a tidal disruption event may be unstable to non-axisymmetric perturbations in the form of the Papaloizou-Pringle instability. We show this can lead to rapid redistribution of angular…
Motivated by recent interesting work on p-mode oscillations in axisymmetric hydrodynamic black-hole tori by Rezzolla, Zanotti, and collaborators, I explore the robustness of these oscillations by means of two and three-dimensional…
We provide a consistent theory of the tachocline confinement (or anisotropic momentum transport) within an hydrodynamical turbulence model. The goal is to explain helioseismological data, which show that the solar tachocline thickness is at…
We investigate the linear axisymmetric viscous overstability in dense planetary rings with typical values of the dynamical optical depth $\tau\gtrsim 0.5$. We develop a granular flow model which accounts for the particulate nature of a…
Developed Navier-Stokes turbulence is simulated with varying wavevector mode reductions. The flatness and the skewness of the velocity derivative depend on the degree of mode reduction. They show a crossover towards the value of the full…