Impact of radial truncation on global 2D hydrodynamic simulations for a Sun-like model

Abstract

Stellar convection is a non-local process responsible for the transport of heat and chemical species. It can lead to enhanced mixing through convective overshooting and excitation of internal gravity waves (IGWs) at convective boundaries. The relationship between these processes is still not well understood and requires global hydrodynamic simulations to capture the important large-scale dynamics. The steep stratification in stellar interiors suggests that the radial extent of such simulations can affect the convection dynamics, the IGWs in the stably stratified radiative zone, and the depth of the overshooting layer. We investigate these effects using two-dimensional global simulations performed with the fully compressible stellar hydrodynamics code MUSIC. We compare eight different radial truncations of the same solar-like stellar model evolved over approximately 400 convective turnover times. We find that the location of the inner boundary has an insignificant effect on the convection dynamics, the convective overshooting and the travelling IGWs. We relate this to the background conditions at the lower convective boundary which are unaffected by the truncation, as long as a significantly deep radiative layer is included in the simulation domain. However, we find that extending the outer boundary by only a few percent of the stellar radius significantly increases the velocity and temperature perturbations in the convection zone, the overshooting depth, the power and the spectral slope of the IGWs. The effect is related to the background conditions at the outer boundary, which are determined in essence by the hydrostatic stratification and the given luminosity.

Accepted in MNRAS 2022 April 29

References in corpus (16)

• Angular momentum transport by heat-driven g-modes in slowly pulsating B stars
• Low-frequency gravity waves in blue supergiants revealed by high-precision space photometry
• On differential rotation and overshooting in solar-like stars
• On the Chemical Mixing Induced by Internal Gravity Waves (IGW)
• Theoretical seismology in 3D : nonlinear simulations of internal gravity waves in solar-like stars
• Numerical Simulations of Penetration and Overshoot in the Sun
• Spectrum and amplitudes of internal gravity waves excited by penetrative convection in solar-type stars
• Lithium depletion in solar-like stars: effect of overshooting based on realistic multi-dimensional simulations
• Fully compressible simulations of waves and core convection in main-sequence stars
• Low-frequency variability in massive stars: Core generation or surface phenomenon?
• Extreme value statistics for two-dimensional convective penetration in a pre-Main Sequence star
• Calibrating Core Overshooting Parameters With Two-dimensional Hydrodynamical Simulations
• Benchmarking the Multi-dimensional Stellar Implicit Code MUSIC
• Spherical-shell boundaries for two-dimensional compressible convection in a star
• Two-dimensional simulations of solar-like models with artificially enhanced luminosity -- I. Impact on convective penetration
• Two-dimensional simulations of solar-like models with artificially enhanced luminosity. II. Impact on internal gravity waves

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• The shape of convection in 2D and 3D global simulations of stellar interiors