Effective viscosity from cloud–cloud collisions in 3D global smoothed particle hydrodynamics simulations

Show simple item record

dc.creator Williamson, David John
dc.creator Thacker, Robert John, 1970-
dc.date.accessioned 2018-04-18T14:55:20Z
dc.date.available 2018-04-18T14:55:20Z
dc.date.issued 2012-04
dc.identifier.issn 0035-8711
dc.identifier.uri http://library2.smu.ca/handle/01/27427
dc.description Publisher's Version/PDF
dc.description.abstract Analytic estimates of the viscous time-scale due to cloud–cloud collisions have been as high as thousands of Gyr. Consequently, cloud collisions are widely ignored as a source of viscosity in galactic discs. However, capturing the hydrodynamics of discs in simple analytic models is a challenge, because of both the wide dynamic range and the importance of 2D and 3D effects. To test the validity of analytic models, we present estimates for the viscous time-scale that are measured from 3D smoothed particle hydrodynamics simulations of disc formation and evolution. We have deliberately removed uncertainties associated with star formation and feedback, thereby enabling us to place lower bounds on the time-scale for this process. We also contrast collapse simulations with results from simulations of initially stable discs and examine the impact of numerical parameters and assumptions on our work, to constrain possible systematics in our estimates. We find that cloud-collision viscous time-scales are in the range of 0.6–16 Gyr, considerably shorter than previously estimated. This large discrepancy can be understood in terms of how the efficiency of collisions is included in the analytical estimates. We find that the viscous time-scale only depends weakly on the number of clouds formed, and so while the viscous time-scale will increase with increasing resolution, this effect is too weak to alter our conclusions. en_CA
dc.language.iso en en_CA
dc.publisher Oxford Academic en_CA
dc.relation.uri https://dx.doi.org/10.1111/j.1365-2966.2012.20465.x
dc.rights This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
dc.subject.lcsh Galactic dynamics
dc.subject.lcsh Interstellar matter
dc.subject.lcsh Hydrodynamics -- Simulation methods
dc.title Effective viscosity from cloud–cloud collisions in 3D global smoothed particle hydrodynamics simulations en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Monthly Notices of the Royal Astronomical Society 421(3), 2170-2186. (2012) en_CA


Files in this item


 

Copyright statement:

 
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
 
Published Version: https://dx.doi.org/10.1111/j.1365-2966.2012.20465.x
 
 

This item appears in the following Collection(s)

Show simple item record