Convective overshooting and penetration in a Boussinesq spherical shell
| Autor: | Nicholas H. Brummell, Pascale Garaud, L. Korre |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Convection
astro-ph.SR FOS: Physical sciences Astronomy & Astrophysics Kinetic energy 01 natural sciences Spherical shell Physics::Fluid Dynamics 0103 physical sciences Thermal Astronomical And Space Sciences Boussinesq approximation (water waves) 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) convection Physics interiors [stars] 010308 nuclear & particles physics Turbulence interior [Sun] Fluid Dynamics (physics.flu-dyn) Astronomy and Astrophysics Mechanics Physics - Fluid Dynamics Amplitude physics.flu-dyn Convection zone Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science |
| Zdroj: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol 484, iss 1 Monthly Notices of the Royal Astronomical Society, vol 484, iss 1 Korre, Lydia; Garaud, Pascale; & Brummell, Nicholas. (2019). Convective overshooting and penetration in a Boussinesq spherical shell. Monthly Notices of the Royal Astronomical Society, 484(1), 1220-1237. doi: 10.1093/mnras/stz047. UC Santa Cruz: Retrieved from: http://www.escholarship.org/uc/item/9xd2x265 |
| DOI: | 10.1093/mnras/stz047. |
| Popis: | Author(s): Korre, L; Garaud, P; Brummell, NH | Abstract: We study the dynamics associated with the extension of turbulent convective motions from a convection zone (CZ) into a stable region (RZ) that lies below the latter. For that purpose, we have run a series of three-dimensional direct numerical simulations solving the Navier-Stokes equations under the Boussinesq approximation in a spherical shell geometry. We observe that the overshooting of the turbulent motions into the stably stratified region depends on three different parameters: the relative stability of the RZ, the transition width between the two, and the intensity of the turbulence. In the cases studied, these motions manage to partially alter the thermal stratification and induce thermal mixing, but not so efficiently as to extend the nominal CZ further down into the stable region. We find that the kinetic energy below the convection zone can be modeled by a half-Gaussian profile whose amplitude and width can be predicted a priori for all of our simulations. We examine different dynamical lengthscales related to the depth of the extension of the motions into the RZ, and we find that they all scale remarkably well with a lengthscale that stems from a simple energetic argument. We discuss the implications of our findings for 1D stellar evolution calculations. |
| Databáze: | OpenAIRE |
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