{
  "id": "1905.07636",
  "version": "v1",
  "published": "2019-05-18T20:06:38.000Z",
  "updated": "2019-05-18T20:06:38.000Z",
  "title": "The interaction between shear and fingering (thermohaline) convection",
  "authors": [
    "P. Garaud",
    "A. Kumar",
    "J. Sridhar"
  ],
  "comment": "Submitted to ApJ",
  "categories": [
    "astro-ph.SR",
    "physics.flu-dyn"
  ],
  "abstract": "Fingering convection is a turbulent mixing process that can occur in stellar radiative regions whenever the mean molecular weight increases with radius. In some cases, it can have a significant observable impact on stellar structure and evolution. The efficiency of mixing by fingering convection as a standalone process has been studied by Brown et al. (2013), but other processes such as rotation, magnetic fields and shear can affect it. In this paper, we present a first study of the effect of shear on fingering (thermohaline) convection in astrophysics. Using Direct Numerical Simulations we find that a moderate amount of shear (that is not intrinsically shear-unstable) always decreases the mixing efficiency of fingering convection, as a result of the tilt it imparts to the fingering structures. We propose a simple analytical extension of the Brown et al. (2013) model in the presence of shear that satisfactorily explains the numerically-derived turbulent compositional mixing coefficient for moderate shearing rates, and can trivially be implemented in stellar evolution codes. We also measure from the numerical simulations a turbulent viscosity, and find that the latter is strongly tied to the turbulent compositional mixing coefficient. Observational implications and caveats of the model are discussed.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-05-18T20:06:38.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "fingering convection",
      "thermohaline",
      "mean molecular weight increases",
      "interaction",
      "numerically-derived turbulent compositional mixing coefficient"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}