Description
To date, the mixing length theory (MLT) is still the most common way to model convection in stars. However, MLT is neglecting important aspects of stellar turbulence. As an alternative, we implemented the turbulent convection theory by Kuhfuss (1987), in the stellar evolution code GARSTEC, which provides a more accurate description of the turbulent flow field in one spatial dimension. Using the GARSTEC models with Kuhfuss convection, we modelled a convectively burning main-sequence star. Subsequently, we set up three-dimensional hydrodynamic simulations based on the stellar models to compare with the results of the turbulent convection theory. These simulations were performed at the nominal luminosity of the star using the SLH (Seven-League-Hydro) code, which specialises in low Mach number flows. The hydrodynamic simulations confirm that the Kuhfuss theory accurately predicts the most relevant quantities for stellar structure and evolution, e.g. the turbulent kinetic energy profile or the morphology of the thermal stratification. We conclude that the Kuhfuss theory is an appropriate description of turbulent convection for stellar models.
