scholarly journals Planet migration, resonant locking, and accretion streams in PDS 70: comparing models and data

2020 ◽  
Vol 499 (2) ◽  
pp. 2015-2027
Author(s):  
Claudia Toci ◽  
Giuseppe Lodato ◽  
Valentin Christiaens ◽  
Davide Fedele ◽  
Christophe Pinte ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Near Infrared ◽  
Scattered Light ◽  
Giant Planets ◽  
Outer Planet ◽  
High Contrast ◽  
Successful Reproduction ◽  
Planet Migration ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

ABSTRACT The disc surrounding PDS 70, with two directly imaged embedded giant planets, is an ideal laboratory to study planet–disc interaction. We present 3D smoothed particle hydrodynamics simulations of the system. In our simulations, planets, which are free to migrate and accrete mass, end up in a locked resonant configuration that is dynamically stable. We show that features observed at infrared (scattered light) and millimetre (thermal continuum) wavelengths are naturally explained by the accretion stream on to the outer planet, without requiring a circumplanetary disc around Planet c. We post-processed our near-infrared synthetic images in order to account for observational biases known to affect high-contrast images. Our successful reproduction of the observations indicates that planet–disc dynamical interactions alone are sufficient to explain the observations of PDS 70.

scholarly journals Planet migration in self-gravitating discs: survival of planets

2020 ◽  
Vol 496 (2) ◽  
pp. 1598-1609 ◽  
Author(s):  
Sahl Rowther ◽  
Farzana Meru
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Three Dimensional ◽  
Cooling Time ◽  
Early Stages ◽  
Simplified Method ◽  
Planet Migration ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Low Mass ◽  
Protoplanetary Discs

ABSTRACT We carry out three-dimensional smoothed particle hydrodynamics simulations to study whether planets can survive in self-gravitating protoplanetary discs. The discs modelled here use a cooling prescription that mimics a real disc, which is only gravitationally unstable in the outer regions. We do this by modelling the cooling using a simplified method such that the cooling time in the outer parts of the disc is shorter than in the inner regions, as expected in real discs. We find that both giant (>MSat) and low-mass (<MNep) planets initially migrate inwards very rapidly, but are able to slow down in the inner gravitationally stable regions of the disc without needing to open up a gap. This is in contrast to previous studies where the cooling was modelled in a more simplified manner where, regardless of mass, the planets were unable to slow down their inward migration. This shows the important effect the thermodynamics has on planet migration. In a broader context, these results show that planets that form in the early stages of the discs’ evolution, when they are still quite massive and self-gravitating, can survive.

scholarly journals Signatures of an eccentric disc cavity: Dust and gas in IRS 48

2019 ◽  
Vol 490 (2) ◽  
pp. 2579-2587 ◽  
Author(s):  
Josh Calcino ◽  
Daniel J Price ◽  
Christophe Pinte ◽  
Nienke van der Marel ◽  
Enrico Ragusa ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Smoothed Particle Hydrodynamics ◽  
High Spatial Resolution ◽  
Contrast Ratio ◽  
High Contrast ◽  
Dust Grains ◽  
Mass Ratio ◽  
Dynamical Interaction ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

ABSTRACT We test the hypothesis that the disc cavity in the ‘transition disc’ Oph IRS 48 is carved by an unseen binary companion. We use 3D dust–gas smoothed-particle hydrodynamics simulations to demonstrate that marginally coupled dust grains concentrate in the gas overdensity that forms in the cavity around a low binary mass ratio binary. This produces high contrast ratio dust asymmetries at the cavity edge similar to those observed in the disc around IRS 48 and other transition discs. This structure was previously assumed to be a vortex. However, we show that the observed velocity map of IRS 48 displays a peculiar asymmetry that is not predicted by the vortex hypothesis. We show the unusual kinematics are naturally explained by the non-Keplerian flow of gas in an eccentric circumbinary cavity. We further show that perturbations observed in the isovelocity curves of IRS 48 may be explained as the product of the dynamical interaction between the companion and the disc. The presence of an ∼0.4 M⊙ companion at an ∼10 au separation can qualitatively explain these observations. High spatial resolution line and continuum imaging should be able to confirm this hypothesis.

Simulation de l'écoulement au cours du procédé de rotomoulage par la méthode Smoothed Particle Hydrodynamics (SPH)

2008 ◽  
Vol 96 (6) ◽  
pp. 263-268 ◽  
Author(s):  
E. Mounif ◽  
V. Bellenger ◽  
A. Ammar ◽  
R. Ata ◽  
P. Mazabraud ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Numerical Simulation of Flow in Complex Geometries by Using Smoothed Particle Hydrodynamics

2020 ◽  
Vol 59 (40) ◽  
pp. 18236-18246
Author(s):  
Tianwen Dong ◽  
Yadong He ◽  
Jianchun Wu ◽  
Shiyu Jiang ◽  
Xingyuan Huang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Smoothed Particle Hydrodynamics ◽  
Complex Geometries ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

scholarly journals Review of smoothed particle hydrodynamics: towards converged Lagrangian flow modelling

2020 ◽  
Vol 476 (2241) ◽  
pp. 20190801
Author(s):  
Steven J. Lind ◽  
Benedict D. Rogers ◽  
Peter K. Stansby
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Graphics Processing Units ◽  
Wave Structure ◽  
Free Form ◽  
Mesh Free ◽  
Weakly Compressible ◽  
Particle Hydrodynamics ◽  
Massively Parallel Computing ◽  
Smoothed Particle ◽  
Graphics Processing

This paper presents a review of the progress of smoothed particle hydrodynamics (SPH) towards high-order converged simulations. As a mesh-free Lagrangian method suitable for complex flows with interfaces and multiple phases, SPH has developed considerably in the past decade. While original applications were in astrophysics, early engineering applications showed the versatility and robustness of the method without emphasis on accuracy and convergence. The early method was of weakly compressible form resulting in noisy pressures due to spurious pressure waves. This was effectively removed in the incompressible (divergence-free) form which followed; since then the weakly compressible form has been advanced, reducing pressure noise. Now numerical convergence studies are standard. While the method is computationally demanding on conventional processors, it is well suited to parallel processing on massively parallel computing and graphics processing units. Applications are diverse and encompass wave–structure interaction, geophysical flows due to landslides, nuclear sludge flows, welding, gearbox flows and many others. In the state of the art, convergence is typically between the first- and second-order theoretical limits. Recent advances are improving convergence to fourth order (and higher) and these will also be outlined. This can be necessary to resolve multi-scale aspects of turbulent flow.

Smoothed particle hydrodynamics versus finite element method for blast impact

2013 ◽  
Vol 61 (1) ◽  
pp. 111-121 ◽  
Author(s):  
T. Jankowiak ◽  
T. Łodygowski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Smoothed Particle Hydrodynamics ◽  
Concrete Slab ◽  
The Finite Element Method ◽  
Particle Hydrodynamics ◽  
Mesh Density ◽  
Smoothed Particle ◽  
Element Method

Abstract The paper considers the failure study of concrete structures loaded by the pressure wave due to detonation of an explosive material. In the paper two numerical methods are used and their efficiency and accuracy are compared. There are the Smoothed Particle Hydrodynamics (SPH) and the Finite Element Method (FEM). The numerical examples take into account the dynamic behaviour of concrete slab or a structure composed of two concrete slabs subjected to the blast impact coming from one side. The influence of reinforcement in the slab (1, 2 or 3 layers) is also presented and compared with a pure concrete one. The influence of mesh density for FEM and the influence of important parameters in SPH like a smoothing length or a particle distance on the quality of the results are discussed in the paper

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