An implicit algorithm for simulating the dynamics of small dust grains with smoothed particle hydrodynamics

Fuente: arXiv
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Autores principales: Elsender, Daniel, Bate, Matthew R.
Formato: Preprint
Publicado: 2024
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author Elsender, Daniel
Bate, Matthew R.
author_facet Elsender, Daniel
Bate, Matthew R.
contents We present an implicit method for solving the diffusion equation for the evolution of the dust fraction in the terminal velocity approximation using dust-as-mixture smoothed particle hydrodynamics (SPH). The numerical scheme involves casting the dust diffusion equation into implicit form, rearranging into its resolvent cubic equation and solving analytically. This method is relevant for small grains that are tightly coupled to the gas, such as sub-micron dust grains in the interstellar medium or millimetre-sized dust grains in protoplanetary discs. The method avoids problems with the variable used to evolve the dust fraction becoming negative when evolved explicitly and is fast and accurate, avoiding the need for dust stopping time limiters and significantly reducing computational expense. Whilst this method is an improvement over using the explicit terminal velocity approximation method, as with any dust-as-mixture method it still fails to give accurate solutions in the limit of large (weakly coupled) grains.
format Preprint
id arxiv_https___arxiv_org_abs_2403_05345
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An implicit algorithm for simulating the dynamics of small dust grains with smoothed particle hydrodynamics
Elsender, Daniel
Bate, Matthew R.
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
We present an implicit method for solving the diffusion equation for the evolution of the dust fraction in the terminal velocity approximation using dust-as-mixture smoothed particle hydrodynamics (SPH). The numerical scheme involves casting the dust diffusion equation into implicit form, rearranging into its resolvent cubic equation and solving analytically. This method is relevant for small grains that are tightly coupled to the gas, such as sub-micron dust grains in the interstellar medium or millimetre-sized dust grains in protoplanetary discs. The method avoids problems with the variable used to evolve the dust fraction becoming negative when evolved explicitly and is fast and accurate, avoiding the need for dust stopping time limiters and significantly reducing computational expense. Whilst this method is an improvement over using the explicit terminal velocity approximation method, as with any dust-as-mixture method it still fails to give accurate solutions in the limit of large (weakly coupled) grains.
title An implicit algorithm for simulating the dynamics of small dust grains with smoothed particle hydrodynamics
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2403.05345