Three-dimensional hydrodynamic Bondi-Hoyle accretion. II. Homogeneous medium at Mach 3 with γ = 5/3

Maximilian Ruffert, W David Arnett

Research output: Contribution to journalArticle

90 Citations (Scopus)

Abstract

We investigate the hydrodynamics of three-dimensional classical Bondi-Hoyle accretion. Totally absorbing spheres of varying sizes (from 10 down to 0.01 accretion radii) move at Mach 3 relative to a homogeneous and slightly perturbed medium, which is taken to be an ideal gas (γ = 5/3). To accommodate the long-range gravitational forces, the extent of the computational volume is 323 accretion radii. We examine the influence of numerical procedure on physical behavior. The hydrodynamics is modeled by the "piecewise parabolic method." No energy sources (nuclear burning) or sinks (radiation, conduction) are included. The resolution in the vicinity of the accretor is increased by multiply nesting several (5-10) grids around the sphere, each finer grid being a factor of 2 smaller in zone dimension that the next coarser grid. The largest dynamic range (ratio of size of the largest grid to size of the finest zone) is 16,384. This allows us to include a coarse model for the surface of the accretor (vacuum sphere) on the finest grid, while at the same time evolving the gas on the coarser grids. Initially (at time t = 0-10), a shock front is set up, a Mach cone develops, and the accretion column is observable. Eventually the flow becomes unstable, destroying axisymmetry. This happens approximately when the mass accretion rate reaches the values (±10%) predicted by the Bondi-Hoyle accretion formula (factor of 2 included). However, our three-dimensional models do not show the highly dynamic flip-flop flow so prominent in two-dimensional calculations performed by other authors. The flow, and thus the accretion rate of all quantities, shows quasi-periodic (P ≈ 5) cycles between quiescent and active states. The interpolation formula proposed in an accompanying paper is found to follow the collected numerical data to within approximately 30%. The specific angular momentum accreted is of the same order of magnitude as the values previously found for two-dimensional flows.

Original languageEnglish (US)
Pages (from-to)351-376
Number of pages26
JournalAstrophysical Journal
Volume427
Issue number1
StatePublished - May 20 1994

Fingerprint

homogeneous medium
hydrodynamics
accretion
grids
Mach cones
flip-flops
two dimensional flow
radii
two-dimensional flow
shock fronts
three dimensional models
ideal gas
energy sources
sinks
gas
angular momentum
dynamic range
interpolation
conduction
vacuum

Keywords

  • Accretion, accretion disks
  • Binaries: close
  • Hydrodynamics
  • Novae, cataclysmic variables
  • Shock waves

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Three-dimensional hydrodynamic Bondi-Hoyle accretion. II. Homogeneous medium at Mach 3 with γ = 5/3. / Ruffert, Maximilian; Arnett, W David.

In: Astrophysical Journal, Vol. 427, No. 1, 20.05.1994, p. 351-376.

Research output: Contribution to journalArticle

@article{a6aeb881db8a41fe8dc6d2c0828a3792,
title = "Three-dimensional hydrodynamic Bondi-Hoyle accretion. II. Homogeneous medium at Mach 3 with γ = 5/3",
abstract = "We investigate the hydrodynamics of three-dimensional classical Bondi-Hoyle accretion. Totally absorbing spheres of varying sizes (from 10 down to 0.01 accretion radii) move at Mach 3 relative to a homogeneous and slightly perturbed medium, which is taken to be an ideal gas (γ = 5/3). To accommodate the long-range gravitational forces, the extent of the computational volume is 323 accretion radii. We examine the influence of numerical procedure on physical behavior. The hydrodynamics is modeled by the {"}piecewise parabolic method.{"} No energy sources (nuclear burning) or sinks (radiation, conduction) are included. The resolution in the vicinity of the accretor is increased by multiply nesting several (5-10) grids around the sphere, each finer grid being a factor of 2 smaller in zone dimension that the next coarser grid. The largest dynamic range (ratio of size of the largest grid to size of the finest zone) is 16,384. This allows us to include a coarse model for the surface of the accretor (vacuum sphere) on the finest grid, while at the same time evolving the gas on the coarser grids. Initially (at time t = 0-10), a shock front is set up, a Mach cone develops, and the accretion column is observable. Eventually the flow becomes unstable, destroying axisymmetry. This happens approximately when the mass accretion rate reaches the values (±10{\%}) predicted by the Bondi-Hoyle accretion formula (factor of 2 included). However, our three-dimensional models do not show the highly dynamic flip-flop flow so prominent in two-dimensional calculations performed by other authors. The flow, and thus the accretion rate of all quantities, shows quasi-periodic (P ≈ 5) cycles between quiescent and active states. The interpolation formula proposed in an accompanying paper is found to follow the collected numerical data to within approximately 30{\%}. The specific angular momentum accreted is of the same order of magnitude as the values previously found for two-dimensional flows.",
keywords = "Accretion, accretion disks, Binaries: close, Hydrodynamics, Novae, cataclysmic variables, Shock waves",
author = "Maximilian Ruffert and Arnett, {W David}",
year = "1994",
month = "5",
day = "20",
language = "English (US)",
volume = "427",
pages = "351--376",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Three-dimensional hydrodynamic Bondi-Hoyle accretion. II. Homogeneous medium at Mach 3 with γ = 5/3

AU - Ruffert, Maximilian

AU - Arnett, W David

PY - 1994/5/20

Y1 - 1994/5/20

N2 - We investigate the hydrodynamics of three-dimensional classical Bondi-Hoyle accretion. Totally absorbing spheres of varying sizes (from 10 down to 0.01 accretion radii) move at Mach 3 relative to a homogeneous and slightly perturbed medium, which is taken to be an ideal gas (γ = 5/3). To accommodate the long-range gravitational forces, the extent of the computational volume is 323 accretion radii. We examine the influence of numerical procedure on physical behavior. The hydrodynamics is modeled by the "piecewise parabolic method." No energy sources (nuclear burning) or sinks (radiation, conduction) are included. The resolution in the vicinity of the accretor is increased by multiply nesting several (5-10) grids around the sphere, each finer grid being a factor of 2 smaller in zone dimension that the next coarser grid. The largest dynamic range (ratio of size of the largest grid to size of the finest zone) is 16,384. This allows us to include a coarse model for the surface of the accretor (vacuum sphere) on the finest grid, while at the same time evolving the gas on the coarser grids. Initially (at time t = 0-10), a shock front is set up, a Mach cone develops, and the accretion column is observable. Eventually the flow becomes unstable, destroying axisymmetry. This happens approximately when the mass accretion rate reaches the values (±10%) predicted by the Bondi-Hoyle accretion formula (factor of 2 included). However, our three-dimensional models do not show the highly dynamic flip-flop flow so prominent in two-dimensional calculations performed by other authors. The flow, and thus the accretion rate of all quantities, shows quasi-periodic (P ≈ 5) cycles between quiescent and active states. The interpolation formula proposed in an accompanying paper is found to follow the collected numerical data to within approximately 30%. The specific angular momentum accreted is of the same order of magnitude as the values previously found for two-dimensional flows.

AB - We investigate the hydrodynamics of three-dimensional classical Bondi-Hoyle accretion. Totally absorbing spheres of varying sizes (from 10 down to 0.01 accretion radii) move at Mach 3 relative to a homogeneous and slightly perturbed medium, which is taken to be an ideal gas (γ = 5/3). To accommodate the long-range gravitational forces, the extent of the computational volume is 323 accretion radii. We examine the influence of numerical procedure on physical behavior. The hydrodynamics is modeled by the "piecewise parabolic method." No energy sources (nuclear burning) or sinks (radiation, conduction) are included. The resolution in the vicinity of the accretor is increased by multiply nesting several (5-10) grids around the sphere, each finer grid being a factor of 2 smaller in zone dimension that the next coarser grid. The largest dynamic range (ratio of size of the largest grid to size of the finest zone) is 16,384. This allows us to include a coarse model for the surface of the accretor (vacuum sphere) on the finest grid, while at the same time evolving the gas on the coarser grids. Initially (at time t = 0-10), a shock front is set up, a Mach cone develops, and the accretion column is observable. Eventually the flow becomes unstable, destroying axisymmetry. This happens approximately when the mass accretion rate reaches the values (±10%) predicted by the Bondi-Hoyle accretion formula (factor of 2 included). However, our three-dimensional models do not show the highly dynamic flip-flop flow so prominent in two-dimensional calculations performed by other authors. The flow, and thus the accretion rate of all quantities, shows quasi-periodic (P ≈ 5) cycles between quiescent and active states. The interpolation formula proposed in an accompanying paper is found to follow the collected numerical data to within approximately 30%. The specific angular momentum accreted is of the same order of magnitude as the values previously found for two-dimensional flows.

KW - Accretion, accretion disks

KW - Binaries: close

KW - Hydrodynamics

KW - Novae, cataclysmic variables

KW - Shock waves

UR - http://www.scopus.com/inward/record.url?scp=12044253276&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=12044253276&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:12044253276

VL - 427

SP - 351

EP - 376

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

ER -