Goldsmith, KJA orcid.org/0000-0002-7679-3348 and Pittard, JM orcid.org/0000-0003-2244-5070 (2017) A comparison of shock-cloud and wind-cloud interactions: the longer survival of clouds in winds. Monthly Notices of the Royal Astronomical Society, 470 (2). pp. 2427-2438. ISSN 0035-8711
Abstract
The interaction of a hot, high-velocity wind with a cold, dense molecular cloud has often been assumed to resemble the evolution of a cloud embedded in a post-shock flow. However, no direct comparative study of these two processes currently exists in the literature. We present 2D adiabatic hydrodynamical simulations of the interaction of a Mach 10 shock with a cloud of density contrast χ = 10 and compare our results with those of a commensurate wind-cloud simulation. We then investigate the effect of varying the wind velocity, effectively altering the wind Mach number Mwind, on the cloud's evolution. We find that there are significant differences between the two processes: 1) the transmitted shock is much flatter in the shock-cloud interaction; 2) a low-pressure region in the wind-cloud case deflects the flow around the edge of the cloud in a different manner to the shock-cloud case; 3) there is far more axial compression of the cloud in the case of the shock. As Mwind increases, the normalized rate of mixing is reduced. Clouds in winds with higher Mwind also do not experience a transmitted shock through the cloud's rear and are more compressed axially. In contrast with shock-cloud simulations, the cloud mixing time normalized by the cloud-crushing time-scale tcc increases for increasing Mwind until it plateaus (at tmix ≃ 25 tcc) at high Mwind, thus demonstrating the expected Mach scaling. In addition, clouds in high Mach number winds are able to survive for long durations and are capable of being moved considerable distances.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017, The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Keywords: | hydrodynamics, shock waves, stars: winds, outflows, ISM: clouds, ISM: kinematics and dynamics |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Funding Information: | Funder Grant number Science & Technology Facilities Council (STFC) ST/L000628/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 22 Jan 2018 11:57 |
Last Modified: | 13 Dec 2024 10:39 |
Status: | Published |
Publisher: | Oxford University Press |
Identification Number: | 10.1093/mnras/stx1431 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:126455 |