A5061279638- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Planetary Science and Exploration
- Magnetic confinement fusion research
- Dust and Plasma Wave Phenomena
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Ionosphere and magnetosphere dynamics
- Fluid Dynamics Simulations and Interactions
- Molecular Spectroscopy and Structure
- Spacecraft Design and Technology
- Aeolian processes and effects
- Computational Fluid Dynamics and Aerodynamics
- Spacecraft and Cryogenic Technologies
- Solar and Space Plasma Dynamics
- Lattice Boltzmann Simulation Studies
- Heat Transfer and Optimization
- Scientific Research and Discoveries
- Video Surveillance and Tracking Methods
- Soil and Unsaturated Flow
- Fluid Dynamics and Heat Transfer
- Heat Transfer Mechanisms
- High-Energy Particle Collisions Research
- Isotope Analysis in Ecology
Ludwig-Maximilians-Universität München
2020-2024
Munich University of Applied Sciences
2024
University of Bern
2018-2022
University of Zurich
2018-2022
Monash University
2018
Swinburne University of Technology
2016
University of Nebraska–Lincoln
2011
University of Maryland, College Park
2011
Trinity College Dublin
2009
Northrop Grumman (United States)
1989-1990
We present Phantom, a fast, parallel, modular and low-memory smoothed particle hydrodynamics magnetohydrodynamics code developed over the last decade for astrophysical applications in three dimensions. The has been with focus on stellar, galactic, planetary high energy astrophysics already used widely studies of accretion discs turbulence, from birth planets to how black holes accrete. Here we describe test core algorithms as well modules magnetohydrodynamics, self-gravity, sink particles,...
We investigate dust entrainment by photoevaporative winds in protoplanetary discs using dusty smoothed particle hydrodynamics. use unequal-mass particles to resolve more than five orders of magnitude disc/outflow density and a one-fluid formulation efficiently simulate an equivalent range drag stopping time. find that only micron-sized grains smaller can be entrained extreme-UV radiation-driven winds. The maximum grain size is set settling the disc rather aerodynamic wind. More generally,...
We study the dynamics of a viscous protoplanetary disc hosting population dust grains with range sizes. compute steady-state solutions, and show that radial motion both gas can deviate substantially from those for single-size population. Although aerodynamic drag on is weaker than in case where all are optimally coupled to gas, cumulative "back-reaction" particles still alter significantly. In typical discs, net effect back-reaction decreases accretion flow compared dust-free (viscous) case,...
We model the behaviour of dust grains entrained by photoevaporation-driven winds from protoplanetary discs assuming a non-rotating, plane-parallel disc. obtain an analytic expression for maximum entrainable grain size in extreme-UV radiation-driven winds, which we demonstrate to be proportional mass-loss rate When compared with our hydrodynamic simulations, reproduces almost all wind properties gas and dust. In typical turbulent discs, sizes are smaller than theoretical everywhere but inner...
We present a new algorithm, MULTIGRAIN, for modelling the dynamics of an entire population small dust grains immersed in gas, typical conditions that are found molecular clouds and protoplanetary discs. The MULTIGRAIN method is more accurate than single-phase simulations because gas experiences backreaction from each phase communicates this change to other phases, thereby indirectly coupling phases together. fast, explicit low storage, requiring only array fractions their derivatives defined...
The Protoplanetary Discussions conference --- held in Edinburgh, UK, from 7th --11th March 2016 included several open sessions led by participants. This paper reports on the discussions collectively concerned with multiphysics modelling of protoplanetary discs, including self-consistent calculation gas and dust dynamics, radiative transfer chemistry. After a short introduction to each these disciplines isolation, we identify series burning questions grand challenges associated their...
We describe a new implementation of the one-fluid method in SPH code Phantom to simulate dynamics dust grains gas protoplanetary discs. revise and extend previously developed algorithms by computing evolution fluid quantity that produces more accurate numerically controlled dynamics. Moreover, limiting stopping time uncoupled violate assumptions terminal velocity approximation, we avoid fatal numerical errors mass conservation. test validate our algorithm running 3D simulations large range...
ABSTRACT We model the gas and dust dynamics in a turbulent protoplanetary disc undergoing extreme-UV photoevaporation order to better characterize properties thermal winds (e.g. size distribution, flux rate, trajectories). Our semi-analytic approach allows us rapidly calculate these without resorting expensive hydrodynamic simulations. find that creates vertical flow within assists turbulence supplying ionization front. examine both delivery of front its subsequent entrainment overlying...
Small grains play an essential role in astrophysical processes such as chemistry, radiative transfer, gas/dust dynamics. The population of small is mainly maintained by the fragmentation process due to colliding grains. An accurate treatment dust required numerical modelling. However, current algorithms for solving equation suffer from over-diffusion conditions 3D simulations. To tackle this challenge, we developed a Discontinuous Galerkin scheme solve efficiently non-linear with limited number bins.
ABSTRACT Dust grains play a significant role in several astrophysical processes, including gas/dust dynamics, chemical reactions, and radiative transfer. Replenishment of small-grain populations is mainly governed by fragmentation during pair-wise collisions between grains. The wide spectrum outcomes, from complete disruption to erosion and/or mass transfer, can be modelled the general non-linear equation. Efficiently solving this equation crucial for an accurate treatment dust numerical...
ABSTRACT Five muffin formulations, liquid whole egg, dry and three commercial egg replacers, which partially replaced in the were evaluated to determine differences product qualities caused by replacers. The products prepared following same procedure other ingredient compositions, except for or replacer used formulation. Physical characteristics sensory properties of samples evaluated. It was found that as an formulation, is critical obtain expected quality characteristics. None replacers...
ABSTRACT Meteoritic studies of Solar system objects show evidence nucleosynthetic heterogeneities that are inherited from small presolar grains ($\lt 10\,\, \mu {\mathrm{m}}$) formed in stellar environments external to our own. The initial distribution and subsequent evolution these currently unconstrained. Using 3D, gas-dust simulations, we find isotopic variations on the order those observed can be generated maintained by drag viscosity. Small dragged radially outwards without size/density...
ABSTRACT The interaction between a YSO stellar magnetic field and its protostellar disc can result in accretional flows outflows from the inner rim. Gas with velocity component perpendicular to mid-plane subject particles centrifugal acceleration away protostar, resulting being catapulted across face of disc. ejected material produce ‘dust fan’, which may be dense enough mimic appearance ‘puffed-up’ We derive analytical equations for time-dependent toroidal field, twist, size stable region,...
Abstract Here, we derive a Parker-wind-like solution for stratified, plane-parallel atmosphere undergoing photoionisation. The difference compared to the standard Parker solar wind is that sonic point crossed only at infinity. simplicity of analytic makes it convenient test problem numerical simulations photoevaporation in protoplanetary discs.
Dust grains play a significant role in several astrophysical processes, including gas/dust dynamics, chemical reactions, and radiative transfer. Replenishment of small-grain populations is mainly governed by fragmentation during pair-wise collisions between grains. The wide spectrum outcomes, from complete disruption to erosion and/or mass transfer, can be modelled the general non-linear equation. Efficiently solving this equation crucial for an accurate treatment dust numerical modelling....
We introduce the Contour Analysis Tool (CAT), a Python toolkit aimed at identifying and analyzing structural elements in density maps. CAT employs various contouring techniques, including lowest-closed contour (LCC), linear logarithmic Otsu thresholding, average gradient thresholding. These contours can aid foreground background segmentation, providing natural limits for both, as well edge detection structure identification. Additionally, provides image processing methods such smoothing,...