Issue |
A&A
Volume 577, May 2015
|
|
---|---|---|
Article Number | A76 | |
Number of page(s) | 8 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361/201425285 | |
Published online | 06 May 2015 |
Shear instabilities in a fully compressible polytropic atmosphere
1 Department of Mathematics, City University London, Northampton Square, London, EC1V 0HB, UK
e-mail: Veronika.Witzke.1@city.ac.uk; Lara.Silvers.1@city.ac.uk
2 Aix-Marseille Université, CNRS, École Centrale Marseille, IPHE UMR 7342, 49 rue F. Joliot-Curie, 13013 Marseille, France
e-mail: Favier@irphe.univ-mrs.fr
Received: 5 November 2014
Accepted: 8 March 2015
Shear flows have a significant impact on the dynamics in an assortment of different astrophysical objects, including accretion discs and stellar interiors. Investigating shear flow instabilities in a polytropic atmosphere provides a fundamental understanding of the motion in stellar interiors where turbulent motions, mixing processes, and magnetic field generation take place. Here, a linear stability analysis for a fully compressible fluid in a two-dimensional Cartesian geometry is carried out. Our study focuses on determining the critical Richardson number for different Mach numbers and the destabilising effects of high thermal diffusion. We find that there is a deviation in the predicted stability threshold for moderate Mach number flows, along with a significant effect on the growth rate of the linear instability for small Péclet numbers. We show that in addition to a Kelvin-Helmholtz instability, a Holmboe instability can appear, and we discuss the implication of this in stellar interiors.
Key words: hydrodynamics / instabilities / Sun: interior
© ESO, 2015
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.