نتایج جستجو برای: midplane
تعداد نتایج: 697 فیلتر نتایج به سال:
Abstract We examine the settled particle layers of planet-forming disks in which streaming instability (SI) is thought to be either weak or inactive. A suite low-to-moderate-resolution 3D simulations a 0.2 H -sized box, where pressure scale height, are performed using PENCIL for two Stokes numbers, St = 0.04 and 0.2, at 1% disk metallicity. find that complex Ekman-layer jet flows emerge subject...
Volatiles, especially CO, are important gas tracers of protoplanetary disks (PPDs). Freeze-out and sublimation processes determine their division between gas and solid phases, which affects both which disk regions can be traced by which volatiles, and the formation and composition of planets. Recently, multiple lines of evidence have suggested that CO is substantially depleted from the gas in t...
Hydromagnetic stresses in accretion discs have been the subject of intense theoretical research over the past one and a half decades. Most of the disc simulations have assumed a small initial magnetic field and studied the turbulence that arises from the magnetorotational instability. However, gaseous discs in galactic nuclei and in some binary systems are likely to have significant initial mag...
This paper presents the application of injection molding of wedge-shaped plates for lightguiding application. This paper discusses the influence of processing parameters on injection molding. The filling stages of lightguide plate for mold flow simulation (3D, midplane) are analyzed. The numerical simulation of mold filling process is based on the concept of control volume finite element method...
The initial stages of planet formation in circumstellar gas discs proceed via dust grains that collide and build up larger and larger bodies1. How this process continues from metre-sized boulders to kilometre-scale planetesimals is a major unsolved problem2: boulders stick together poorly3, and spiral into the protostar in a few hundred orbits due to a head wind from the slower rotating gas4. G...
Gravitational forces are expected to excite spiral density waves in protoplanetary disks, disks of gas and dust orbiting young stars. However, previous observations that showed spiral structure were not able to probe disk midplanes, where most of the mass is concentrated and where planet formation takes place. Using the Atacama Large Millimeter/submillimeter Array, we detected a pair of trailin...
We study the vertical settling of solid bodies in a turbulent protoplanetary disc. We consider the situation when the coupling to the gas is weak or equivalently when the particle stopping time τst due to friction with the gas is long compared to the orbital timescale Ω. An analytical model, which takes into account the stochastic nature of the sedimentation process using a Fokker-Planck equati...
This paper describes the process of pattern selection between rolls and hexagons in Rayleigh-l~nard convection with reflectional symmetry in the horizontal midplane. This symmetry is a consequence of the Boussinesq approximation, provided the boundary conditions are the same on the top and bottom plates. All possible local bifurcation diagrams (assuming certain non-degeneracy conditions) are fo...
We propose that UV radiation can stimulate the formation of planetesimals in externally-illuminated protoplanetary disks. We present a numerical model of disk evolution including vertical sedimentation and photo-evaporation by an external O or B star. As solid material grows and settles toward the disk midplane, the outer layers of the disk become dust depleted. When such a disk is exposed to U...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید