Related papers: Particle Aggregation in a turbulent Keplerian flow
Local generation of vorticity occurs in rotating density-stratified fluids as fluid parcels move radially, expanding or contracting with respect to the background density stratification. Thermal convection in rotating 2D equatorial…
The origin of planetesimals ($\sim$100 km planet building blocks) has confounded astronomers for decades, as numerous growth barriers appear to impede their formation. In a recent paper we proposed a novel interaction where the streaming…
A type of polar self-propelled particle generates a torque that makes it naturally drawn to higher-density areas. The collective behaviour this induces in assemblies of particles constitutes a new form of phase separation in active fluids.
It has been realized in recent years that the accretion of pebble-sized dust particles onto planetary cores is an important mode of core growth, which enables the formation of giant planets at large distances and assists planet formation in…
We present a simple model for low-mass planet formation and subsequent evolution within "transition" discs. We demonstrate quantitatively that the predicted and observed structure of such discs are prime birthsites of planets. Planet…
There is a clear distinction between simple laminar and complex turbulent fluids. But in some cases, as for the nocturnal planetary boundary layer, a stable and well-ordered flow can develop intense and sporadic bursts of turbulent activity…
Quantum vortices with more than a single circulation quantum are usually unstable and decay into clusters of smaller vortices. One way to prevent the decay is to place the vortex at the centre of a convergent (draining) fluid flow, which…
The formation of astrophysical structures, such as stars, compact objects but also galaxies, entail an,enhancement of densities by many orders of magnitude which occurs through gravitational collapse. The role played by turbulence during…
We explore here the idea, reminiscent in some respect of Von Weizsacker's (1944) and Alfven's (1976) outmoded cosmogonies, that long-lived vortices in a turbulent protoplanetary nebula can capture large amount of solid particles and…
In dense flowing bidisperse particle mixtures varying in size or density alone, smaller particles sink (driven by percolation) and lighter particles rise (driven by buoyancy). But when the particle species differ from each other in both…
We review the main results from recent numerical simulations of turbulent fragmentation and star formation. Specifically, we discuss the observed scaling relationships, the ``quiescent'' (subsonic) nature of many star-forming cores, their…
It is believed that planets are formed by aggregation of dust particles suspended in the turbulent gas forming accretion disks around developing stars. We describe a mechanism, termed 'Stokes trapping', by which turbulence limits the growth…
When a planar shock wave interacts with a random pattern of pre-shock density non-uniformities, it generates an anisotropic turbulent velocity/vorticity field. This turbulence plays an important role at the early stages of the mixing…
Proposed mechanisms for the formation of km-sized solid planetesimals face long-standing difficulties. Robust sticking mechanisms that would produce planetesimals by coagulation alone remain elusive. The gravitational collapse of smaller…
Turbulence plays a key role in the transport of pebble-sized particles. It also affects the ability of pebbles to be accreted by protoplanets, because it stirs pebbles out of the disk midplane. In addition, turbulence can suppress pebble…
Vortices are believed to greatly help the formation of km sized planetesimals by collecting dust particles in their centers. However, vortex dynamics is commonly studied in non-self-gravitating disks. The main goal here is to examine the…
In the multi-scale view of the star formation process the material flows from large molecular clouds down to clumps and cores. In this paradigm it is still unclear if it is gravity or turbulence that drives the observed supersonic…
The role of the spatial structure of a turbulent flow in enhancing particle collision rates in suspensions is an open question. We show and quantify, as a function of particle inertia, the correlation between the multiscale structures of…
Interpenetrating streams of solids and gas in a Keplerian disk produce a local, linear instability. The two components mutually interact via aerodynamic drag, which generates radial drift and triggers unstable modes. The secular instability…
Turbulence and turbulent mixing of temperature powered the big bang formation of the universe at Planck length, time, and temperature scales. Planck-Kerr inertial-vortex forces balanced Planck gravitational forces to produce Planck…