Shear mixing in stellar radiative zones - II. Robustness of numerical simulations

Abstract

Recent numerical simulations suggest that the model by Zahn (1992, A&A, 265, 115) for the turbulent mixing of chemical elements due to differential rotation in stellar radiative zones is valid. We investigate the robustness of this result with respect to the numerical configuration and Reynolds number of the flow. We compare results from simulations performed with two different numerical codes, including one that uses the shearing-box formalism. We also extensively study the dependence of the turbulent diffusion coefficient on the turbulent Reynolds number. The two numerical codes used in this study give consistent results. The turbulent diffusion coefficient is independent of the size of the numerical domain if at least three large turbulent structures fit in the box. Generally, the turbulent diffusion coefficient depends on the turbulent Reynolds number. However, our simulations suggest that an asymptotic regime is obtained when the turbulent Reynolds number is larger than $10^3$. Shear mixing in the regime of small Péclet numbers can be investigated numerically both with shearing-box simulations and simulations using explicit forcing. Our results suggest that Zahn's model is valid at large turbulent Reynolds numbers.

8 pages, 8 figures, accepted by A&A

References in corpus (12)

• The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars
• White dwarf spins from low mass stellar evolution models
• Angular Momentum Transport via Internal Gravity Waves in Evolving Stars
• The MiMeS Survey of Magnetism in Massive Stars: CNO surface abundances of Galactic O stars
• Angular momentum redistribution by mixed modes in evolved low-mass stars. II. Spin-down of the core of red giants induced by mixed modes
• Turbulent transport in radiative zones of stars
• The Role of the Magnetorotational Instability in Massive Stars
• Numerical simulations of the magnetorotational instability in protoneutron stars: I. Influence of buoyancy
• 3D evolution of magnetic fields in a differentially rotating stellar radiative zone
• Shear mixing in stellar radiative zones I. Effect of thermal diffusion and chemical stratification
• Fingering Convection in Red Giants Revisited
• Attempts to reproduce the rotation profile of the red giant KIC 7341231 observed by Kepler

Cited by in corpus (27)

• The shape of convective core overshooting from gravity-mode period spacings
• Anisotropic turbulent transport in stably stratified rotating stellar radiation zones
• Lithium depletion and angular momentum transport in solar-type stars
• Angular Momentum Transport in Proto-Neutron Stars and the Fate of Neutron Star Merger Remnants
• Turbulent transport by diffusive stratified shear flows: from local to global models. Part I: Numerical simulations of a stratified plane Couette flow
• The dynamics of stratified horizontal shear flows at low Péclet number
• 3D hydrodynamic simulations of massive main-sequence stars. I. Dynamics and mixing of convection and internal gravity waves
• The effects of surface fossil magnetic fields on massive star evolution: IV. Grids of models at Solar, LMC, and SMC metallicities
• Horizontal shear instabilities at low Prandtl number
• Horizontal shear instabilities in rotating stellar radiation zones: I. Inflectional and inertial instabilities and the effects of thermal diffusion
• Horizontal shear instabilities in rotating stellar radiation zones: II. Effects of the full Coriolis acceleration
• 3D hydrodynamics simulations of internal gravity waves in red giant branch stars
• Testing a one-dimensional prescription of dynamical shear mixing with a two-dimensional hydrodynamic simulation
• The interaction between shear and fingering (thermohaline) convection
• Enhanced Rotational Mixing in the Radiative Zones of Massive Stars
• Turbulent transport by diffusive stratified shear flows: from local to global models. Part II: Limitations of local models
• Angular momentum transport, layering, and zonal jet formation by the GSF instability: nonlinear simulations at a general latitude
• Turbulent transport by diffusive stratified shear flows: from local to global models. III. A closure model
• Small-Scale Dynamo in Stably Stratified Turbulence
• Critical Balance and Scaling of Strongly Stratified Turbulence at Low Prandtl Number
• Modeling coexisting GSF and shear instabilities in rotating stars
• Stably stratified exact coherent structures in shear flow: the effect of Prandtl number
• Anisotropic turbulent transport with horizontal shear in stellar radiative zones
• Stress-driven spin-down of a viscous fluid within a spherical shell
• The Impact of Neutrino Magnetic Moments on the Evolution of the Helium Flash and Lithium-Rich Red Clump Stars
• Using Lithium and Beryllium to Study Structure and Evolution of Rotating Stars
• Evolution and characteristics of forced shear flows in polytropic atmospheres: Large and small Péclet number regimes