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In the outer envelope of the Sun and in other stars, differential rotation and meridional circulation are maintained via the redistribution of momentum and energy by convective motions. In order to properly capture such processes in a…

Astrophysics · Physics 2009-11-13 M. S. Miesch

We explore the effects of an outer stably stratified coronal envelope on rotating turbulent convection, differential rotation, and large-scale dynamo action in spherical wedge models of the Sun. We solve the compressible magnetohydrodynamic…

Solar and Stellar Astrophysics · Physics 2016-12-20 Jörn Warnecke , Petri J. Käpylä , Maarit J. Käpylä , Axel Brandenburg

The rate at which small inertial particles collide with a moderate-Reynolds-number spherical body is found to be strongly affected when the formers are also settling under the effect of gravity. The sedimentation of small particles indeed…

Fluid Dynamics · Physics 2020-09-08 Jeremie Bec , Christoph Siewert , Robin Vallee

We discuss recent advances made in modelling the complex magnetohydrodynamics of the Sun using our anelastic spherical harmonics (ASH) code. We have conducted extensive 3--D simulations of compressible convection in rotating spherical…

Astrophysics · Physics 2007-05-23 Allan Sacha Brun , Juri Toomre

In the solar convection zone, rotation couples with intensely turbulent convection to build global-scale flows of differential rotation and meridional circulation. Our sun must have rotated more rapidly in its past, as is suggested by…

Turbulent convection in the interiors of the Sun and the Earth occurs at high Rayleigh numbers $Ra$, low Prandtl numbers $Pr$, and different levels of rotation rates. To understand the combined effects better, we study rotating turbulent…

Fluid Dynamics · Physics 2024-11-20 Ambrish Pandey , Katepalli R. Sreenivasan

Much work has been done to understand the settling dynamics of spherical particles in a homogeneous and a stratified fluid. However, the effects of shape anisotropy on the settling dynamics of a particle in a stratified fluid are not…

Fluid Dynamics · Physics 2025-01-23 Rishabh V. More , Mehdi N. Ardekani , Luca Brandt , Arezoo M. Ardekani

We present three-dimensional MHD simulations of buoyant magnetic flux tubes that rise through a stratified model convection zone in the presence of solar rotation. The equations of MHD are solved in the anelastic approximation, and the…

Astrophysics · Physics 2009-10-31 W. P. Abbett , G. H. Fisher , Y. Fan

We study the influence of stratification on stellar turbulent convection near the stellar surface and in depth by carrying out 3D high resolution hydrodynamic simulations with the ASH code. Four simulations with different radial density…

Solar and Stellar Astrophysics · Physics 2015-05-27 Nicolas Bessolaz , Allan Sacha Brun

We consider strongly stratified forced turbulence in a plane-parallel layer with helicity and corresponding large-scale dynamo action in the lower part and non-helical turbulence in the upper. The magnetic field is found to develop strongly…

Solar and Stellar Astrophysics · Physics 2016-05-23 Sarah Jabbari , Axel Brandenburg , Dhrubaditya Mitra , Nathan Kleeorin , Igor Rogachevskii

This paper considers the dominant dynamical, thermal and rotational balances within the solar convection zone. The reasoning is such that: Coriolis forces balance pressure gradients. Background vortex stretching, baroclinic torques and…

Solar and Stellar Astrophysics · Physics 2020-10-30 Geoffrey M. Vasil , Keith Julien , Nicholas A. Featherstone

We study how stably stratified or semi-convective layers alter tidal dissipation rates associated with the generation of inertial, gravito-inertial, interfacial and surface gravity waves in rotating giant planets. We explore scenarios in…

Earth and Planetary Astrophysics · Physics 2023-11-07 Christina M. Pontin , Adrian J. Barker , Rainer Hollerbach

The role of short-wave instabilities on geostrophic turbulence is studied in a simplified model consisting of three layers in the quasi-geostrophic approximation. The linear stability analysis shows that short-wave instabilities are created…

Fluid Dynamics · Physics 2015-10-21 Gualtiero Badin

Numerical MHD simulations play increasingly important role for understanding mechanisms of stellar magnetism. We present simulations of convection and dynamos in density-stratified rotating spherical fluid shells. We employ a new 3D…

Solar and Stellar Astrophysics · Physics 2015-09-03 Radostin D. Simitev , Alexander G. Kosovichev , Friedrich H. Busse

(abridged) Context: Rotation is thought to influence the size of convective eddies and the efficiency of convective energy transport in the deep convection zones of stars. Rotationally constrained convection has been invoked to explain the…

Solar and Stellar Astrophysics · Physics 2023-10-20 Petri J. Käpylä

The nonlinear coupling between stellar convection and rotation is of great interest because it relates to understanding both stellar evolution and activity. We investigated the influence of rotation and the Coriolis force on the dynamics…

Solar and Stellar Astrophysics · Physics 2025-02-12 Irina N. Kitiashvili , Alexander G. Kosovichev , Alan A. Wray

We study the effect of particle shape on the turbulence in suspensions of spheroidal particles at volume fraction $\phi = 10\%$ and show how the near-wall particle dynamics deeply changes with the particle aspect ratio and how this affects…

Fluid Dynamics · Physics 2018-09-07 M. Niazi Ardekani , L. Brandt

We present a series of 3-D nonlinear simulations of solar-like convection, carried out using the Anelastic Spherical Harmonic (ASH) code, that are designed to isolate those processes that drive and shape meridional circulations within…

Solar and Stellar Astrophysics · Physics 2015-05-20 Nicholas A. Featherstone , Mark S. Miesch

Rayleigh-Benard convection in a rotating spherical shell provides a simplified model for convective dynamics of planetary and stellar interiors. In this study, we build more than 200 numerical models of rotating convection in a spherical…

Fluid Dynamics · Physics 2025-08-14 Wei Fan , Qi Wang , Yufeng Lin

The solar tachocline is a shear layer located at the base of the solar convection zone. The horizontal shear in the tachocline is likely turbulent, and it is often assumed that this turbulence would be strongly anisotropic as a result of…

Solar and Stellar Astrophysics · Physics 2021-01-20 Pascale Garaud