Related papers: Turbulent Convective Cepheid Models: Linear Proper…
A computational fluid model is developed to study waves and instabilities. A new technique involving initial perturbations in configuration space have been implemented to excite the plasma waves; i.e. the perturbations acting similar to a…
Turbulent motions in the interior of a star play an important role in its evolution, since they transport chemical species, thermal energy and angular momentum. Our overall goal is to construct a practical turbulent closure model for…
Evolutionary tracks for 2-8M$_\odot$ models, covering a [Fe/H]=$-$1.0 ($Z=0.0014$) to [Fe/H]=+0.2 ($Z=0.02$) metallicity range are computed with Modules for Experiments in Stellar Astrophysics, MESA, to investigate evolutionary and…
Three dimensional hydrodynamic simulations of full amplitude RR Lyrae stars have been computed for several models across the instability strip. The three dimensional nature of the calculations allows convection to be treated without…
We investigate simulated turbulent flow within thermally driven stellar convection zones. Different driving sources are studied, including cooling at the top of the convectively unstable region, as occurs in surface convection zones; and…
A simplified model for stellar and planetary convection is derived for the magnitude of the rms velocity, degree of superadiabaticity, and characteristic length scale with Rossby number as well as with thermal and viscous diffusivities.…
Pulsating stars are universally recognized as precise distance indicators and tracers of stellar populations. Their variability, combined with well-defined relationships between pulsation properties and intrinsic evolutionary parameters…
We present an analysis of the response of a radiative region to waves generated by a convective region of the star; this wave treatment of the classical problem of ``overshooting'' gives extra mixing relative to the treatment traditionally…
Turbulent Rayleigh-Benard convection with phase changes in an extended layer between two parallel impermeable planes is studied by means of three-dimensional direct numerical simulations for Rayleigh numbers between 10^4 and 1.5\times 10^7…
We present multidimensional modeling of convection and oscillations in main-sequence stars somewhat more massive than the Sun, using three separate approaches: 1) Using the 3-D planar StellarBox radiation hydrodynamics code to model the…
We simulate the nonlinear hydrodynamical evolution of tidally-excited inertial waves in convective envelopes of rotating stars and giant planets modelled as spherical shells containing incompressible, viscous and adiabatically-stratified…
Context: We study the impact of two-dimensional spherical shells on compressible convection. Realistic profiles for density and temperature from a one-dimensional stellar evolution code are used to produce a model of a large stellar…
Convection is ubiquitous in stars and occurs under many different conditions. Here we explore convection in main-sequence stars through two lenses: dimensionless parameters arising from stellar structure and parameters which emerge from the…
By using a non-local and time-dependent convection theory, we have calculated radial and low-degree non-radial oscillations for stellar evolutionary models with $M=1.4$--3.0\,$\mathrm{M}_\odot$. The results of our study predict theoretical…
Analyses of recent observations of the sole classical Cepheid in the Kepler field, V1154 Cygni, found random changes of about 30 minutes in the pulsation period. These period changes challenge standard theories of pulsation and evolution…
Hydrodynamic computations of nonlinear Cepheid pulsation models with periods from 20 to 100 day on the evolutionary stage of core helium burning were carried out. Equations of radiation hydrodynamics and time--dependent convection were…
Modelling amplitudes of stochastically excited oscillations in stars is a powerful tool for understanding the properties of the convective zones. For instance, it gives us information on the way turbulent eddies are temporally correlated in…
We present a new extended and detailed set of models for Classical Cepheid pulsators at solar chemical composition ($Z=0.02$, $Y=0.28$) based on a well tested nonlinear hydrodynamical approach. In order to model the possible dependence on…
A numerical study of the Kelvin-Helmholtz instability in compressible magnetohydrodynamics is presented. The three-dimensional simulations consider shear flow in a cylindrical jet configuration, embedded in a uniform magnetic field directed…
We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of…