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In this paper, we carry a detailed study of mechanical systems with configuration space $Q\longrightarrow Q/G$ for which the base $Q/G$ variables are being controlled. The overall system's motion is considered to be induced from the base…

Mathematical Physics · Physics 2009-11-13 Alejandro Cabrera

We numerically examine dynamo action generated by a flow of an electrically conducting fluid in a precessing cylindrical cavity. We compare a simplified kinematic approach based on the solution of the magnetic induction equation with a…

Fluid Dynamics · Physics 2025-04-07 André Giesecke , Mike Wilbert , Ján Šimkanin , Rainer Grauer , Frank Stefani

Convection is the main heat transport mechanism in the Earth's liquid core and is thought to power the dynamo that generates the geomagnetic field. Core convection is strongly constrained by rotation while being turbulent. Given the…

Fluid Dynamics · Physics 2025-02-28 Céline Guervilly , Emmanuel Dormy

The amplification of astrophysical magnetic fields takes place via dynamo instability in turbulent environments. The presence of vorticity is crucial for the dynamo to happen. However, the role of vorticity is not yet fully understood. This…

Astrophysics of Galaxies · Physics 2024-12-11 Albert Elias-López , Fabio del Sordo , Daniele Viganò

Planets and stars are able to generate coherent large-scale magnetic fields by helical convective motions in their interiors. This process, known as hydromagnetic dynamo, involves nonlinear interaction between the flow and magnetic field.…

Fluid Dynamics · Physics 2025-05-13 Anna Guseva , Ludovic Petitdemange , Steven M. Tobias

The dipole-multipole transition in rapidly rotating dynamos is investigated through the analysis of forced magnetohydrodynamic waves in an unstably stratified fluid. The focus of this study is on the inertia-free limit applicable to…

Fluid Dynamics · Physics 2023-09-25 Debarshi Majumder , Binod Sreenivasan , Gaurav Maurya

Context: observations of rapidly rotating M dwarfs show a broad variety of large-scale magnetic fields encompassing dipole-dominated and multipolar geometries. In dynamo models, the relative importance of inertia in the force balance --…

Solar and Stellar Astrophysics · Physics 2015-06-12 T. Gastine , J. Morin , L. Duarte , A. Reiners , U. R. Christensen , J. Wicht

Magnetic field observations of low-mass stars reveal an increase of magnetic activity with increasing rotation rate. The so-called activity-rotation relation is usually attributed to changes in the underlying dynamo processes generating the…

Solar and Stellar Astrophysics · Physics 2015-06-12 Martin Schrinner

This paper introduces a novel dynamical model, building upon the existing dynamical model for Deimos in the current numerical ephemerides, which only encompasses the simple libration effects of Deimos. The study comprehensively incorporates…

Earth and Planetary Astrophysics · Physics 2024-04-17 Kai Huang , Lijun Zhang , Yongzhang Yang , Mao Ye , Yuqiang Li

This paper presents a method to control a manipulator system grasping a rigid-body payload so that the motion of the combined system in consequence of externally applied forces to be the same as another free-floating rigid-body (with…

Robotics · Computer Science 2022-09-20 Farhad Aghili

We have performed numerical simulations of boundary-driven dynamos using a three-dimensional non-linear magnetohydrodynamical model in a spherical shell geometry. A conducting fluid of magnetic Prandtl number Pm=0.01 is driven into motion…

Fluid Dynamics · Physics 2012-11-02 Céline Guervilly , Nicholas H. Brummell

An update is given on the current status of solar and stellar dynamos. At present, it is still unclear why stellar cycle frequencies increase with rotation frequency in such a way that their ratio increases with stellar activity. The…

Solar and Stellar Astrophysics · Physics 2015-06-15 Axel Brandenburg

We present analytical examples of fluid dynamos that saturate through the action of the Coriolis and inertial terms of the Navier-Stokes equation. The flow is driven by a body force and is subject to global rotation and uniform sweeping…

Fluid Dynamics · Physics 2019-03-27 Kannabiran Seshasayanan , Basile Gallet

Magnetic fields of low-mass stars and planets are thought to originate from self-excited dynamo action in their convective interiors. Observations reveal a variety of field topologies ranging from large-scale, axial dipole to more…

Solar and Stellar Astrophysics · Physics 2015-06-04 Martin Schrinner , Ludovic Petitdemange , Emmanuel Dormy

In dynamo power-based scaling laws, the power $P$ injected by buoyancy forces is measured by a so-called flux-based Rayleigh number, denoted as ${\rm Ra}_Q^*$ (see Christensen and Aubert, 2006). Whereas it is widely accepted that this…

Fluid Dynamics · Physics 2016-11-22 Ludivine Oruba

Increasing evidence is becoming available about not only the surface differential rotation of rapidly rotating cool stars but, in a small number of cases, also about temporal variations, which possibly are analogous to the solar torsional…

Astrophysics · Physics 2009-11-10 E. Covas , D. Moss , R. Tavakol

At small but supercritical Rayleigh numbers, simulations of dynamos in spherical shells often separate into two broad regimes characterised either by their relative magnetic field strength (weak/strong) or by their dominant force balance…

Fluid Dynamics · Physics 2026-03-18 Luke J. Gostelow , Robert J. Teed

The interaction of trailing and leading vortex structures in low Reynolds number forced (varicose) jet with coflow is studied using Direct Numerical Simulation (DNS), where we report the dynamics of these vortices for a range of varying…

Fluid Dynamics · Physics 2021-01-22 Bharat Bhatia , Ashoke De

The increasing threat raised by space debris led to the development of different mathematical models and approaches to investigate the dynamics of small particles orbiting around the Earth. Such models and methods strongly depend on the…

Earth and Planetary Astrophysics · Physics 2017-04-05 Alessandra Celletti , Christos Efthymiopoulos , Fabien Gachet , Catalin Gales , Giuseppe Pucacco

The dynamics of large-scale geophysical fluids is primarily governed by the balance between the Coriolis force and the pressure gradient. This phenomenon, known as geostrophic equilibrium, is the basis for the geostrophic model, which has…

Atmospheric and Oceanic Physics · Physics 2025-10-21 Alejandro González del Pino , Manuel Jesús Castro Díaz , Jorge Macías Sánchez