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A fission decay of highly excited periodically driven compound nuclei is considered in the framework of Langevin approach. We have used residual-time distribution (RTD) as the tool for studying of dynamic features in a presence of periodic…

Chaotic Dynamics · Physics 2007-05-23 V. P. Berezovoj , Yu. L. Bolotin , O. P. Dzyubak , V. V. Yanovsky , A. V. Zhiglo

We introduce a novel type of random perturbation for the classical Lorenz flow in order to better model phenomena slowly varying in time such as anthropogenic forcing in climatology and prove stochastic stability for the unperturbed flow.…

Dynamical Systems · Mathematics 2020-06-09 Michele Gianfelice , Sandro Vaienti

Variational integrators are a special kind of geometric discretisation methods applicable to any system of differential equations that obeys a Lagrangian formulation. In this thesis, variational integrators are developed for several…

Numerical Analysis · Mathematics 2014-12-08 Michael Kraus

We construct sub-grid scale models of incompressible fluids by considering expectations of semi-martingale Lagrangian particle trajectories. Our construction is based on the Lagrangian decomposition of flow maps into mean and fluctuation…

Mathematical Physics · Physics 2025-04-15 Theo Diamantakis , Ruiao Hu

This paper investigates stochastic solenoidal magnetohydrodynamics within the field-theoretic Martin-Siggia-Rose-De Dominicis-Janssen formalism, with a specific focus on the stability of the system when spatial mirror (parity) symmetry is…

Inertial particles in turbulent flows are characterised by preferential concentration and segregation and, at sufficient mass loading, dense particle clusters may spontaneously arise due to momentum coupling between the phases. These…

Fluid Dynamics · Physics 2019-01-30 Alessio Innocenti , Rodney O Fox , Sergio Chibbaro

We study the dynamics of inertial particles in turbulence using datasets obtained from both direct numerical simulations and laboratory experiments of turbulent swirling flows. By analyzing time series of particle velocity increments at…

The Lagrangian properties of the velocity field in a magnetized fluid are studied using three-dimensional simulations of a helical magnetohydrodynamic dynamo. We compute the attracting and repelling Lagrangian coherent structures, which are…

Solar and Stellar Astrophysics · Physics 2012-07-10 Erico L. Rempel , Abraham C. -L. Chian , Axel Brandenburg

The two-fluid Maxwell system couples frictionless electron and ion fluids via Maxwell's equations. When the frequencies of light waves, Langmuir waves, and single-particle cyclotron motion are scaled to be asymptotically large, the…

Plasma Physics · Physics 2017-08-02 J. W. Burby

Direct numerical simulations of incompressible nonhelical randomly forced MHD turbulence are used to demonstrate for the first time that the fluctuation dynamo exists in the limit of large magnetic Reynolds number Rm>>1 and small magnetic…

As three particles are advected by a turbulent flow, they separate from each other and develop non trivial geometries, which effectively reflect the structure of the turbulence. We investigate here the geometry, in a statistical sense, of…

Chaotic Dynamics · Physics 2007-05-23 M. A. I. Khan , A. Pumir , J. C. Vassilicos

With the help of a model of magnetohydrodynamic (MHD) turbulence tested previously, we explore high Reynolds number regimes up to equivalent resolutions of 6000^3 grid points in the absence of forcing and with no imposed uniform magnetic…

Fluid Dynamics · Physics 2015-03-19 J. Pietarila Graham , P. D. Mininni , A. Pouquet

We derive a collisionless kinetic theory for an ensemble of molecules undergoing nonholonomic rolling dynamics. We demonstrate that the existence of nonholonomic constraints leads to problems in generalizing the standard methods of…

Chaotic Dynamics · Physics 2013-02-26 Darryl D. Holm , Vakhtang Putkaradze , Cesare Tronci

We present numerical simulations of laminar and turbulent channel flow of an elastoviscoplastic fluid. The non-Newtonian flow is simulated by solving the full incompressible Navier-Stokes equations coupled with the evolution equation for…

Fluid Dynamics · Physics 2018-07-17 Marco Edoardo Rosti , Daulet Izbassarov , Outi Tammisola , Sarah Hormozi , Luca Brandt

Particles in turbulence frequently encounter extreme accelerations between extended periods of quiescence. The occurrence of extreme events is closely related to the intermittent spatial distribution of intense flow structures such as…

Fluid Dynamics · Physics 2019-08-29 Lukas Bentkamp , Cristian C. Lalescu , Michael Wilczek

In this paper we study the Hamiltonian dynamics of charged particles subject to a non-self-consistent stochastic electric field, when the plasma is in the so-called weak turbulent regime. We show that the asymptotic limit of the Vlasov…

Analysis of PDEs · Mathematics 2021-10-13 Claude Bardos , Nicolas Besse

How stochastic, microscopic events generate deterministic, macroscopic properties is a fundamental question in physics. We address this question by developing a quantum master equation model for concentrated radical solutions, where random…

Chemical Physics · Physics 2026-05-26 Yoshiaki Uchida , Ryohei Kishi

A simple generalization of the MHD model accounting for the fluctuations of the configurations due to kinetic effects in plasmas in short times small scales is considered. The velocity of conductive fluid and the magnetic field are…

Plasma Physics · Physics 2007-10-26 D. Volchenkov , R. Lima

Based on direct numerical simulations with point-like inertial particles, with Stokes numbers, $\textrm{St}=0, 0.5$, $3$, and $6$, transported by homogeneous and isotropic turbulent flows, we present in this letter for the first time…

Fluid Dynamics · Physics 2022-06-27 A. Fuchs , M. Obligado , M. Bourgoin , M. Gibert , P. D. Mininni , J. Peinke

In this work, we propose a model for the orientation of inertialess spheroidal particles suspended in turbulent flows. This model consists in a stochastic version of the Jeffery equation that can be included in a statistical Lagrangian…

Fluid Dynamics · Physics 2023-03-31 Lorenzo Campana , Mireille Bossy , Christophe Henry