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We discuss the behavior of partially wetting liquids on a rotating cylinder using a model that takes into account the effects of gravity, viscosity, rotation, surface tension and wettability. Such a system can be considered as a prototype…

Fluid Dynamics · Physics 2018-07-24 Te-Sheng Lin , Steven Rogers , Dmitri Tseluiko , Uwe Thiele

We analytically examine fluctuations of vorticity excited by an external random force in two-dimensional fluid. We develop the perturbation theory enabling one to calculate nonlinear corrections to correlation functions of the flow…

Fluid Dynamics · Physics 2024-03-28 I. V. Kolokolov , V. V. Lebedev , V. M. Parfenyev

Force fluctuations in granular materials are investigated. A continuum equation is derived starting from a discrete model proposed in the literature. The influence of boundary conditions is investigated. For periodic boundary conditions the…

Condensed Matter · Physics 2007-05-23 Alexei Vazquez , Jose Marin-Antuña , O. Sotolongo-Costa

The existence of outflow in accretion flows is confirmed by observations and magnetohydrodynamics (MHD) simulations. In this paper, we study outflows of accretion flows in the presence of resistivity and toroidal magnetic field. The…

High Energy Astrophysical Phenomena · Physics 2012-05-11 Kazem Faghei , Azam Mollatayefeh

Highly nonlinear behavior of a system of discrete sites on a lattice is observed when a specific feedback loop is introduced into models employing coupled map lattices, quantum cellular automata, or the real-valued analogues of the latter.…

Adaptation and Self-Organizing Systems · Physics 2007-05-23 Siegfried Fussy , Gerhard Groessing , Herbert Schwabl

In the paper the rescaled occupation time fluctuation process of a certain empirical system is investigated. The system consists of particles evolving independently according to \alpha-stable motion in R^d, \alpha<d<2\alpha. The particles…

Probability · Mathematics 2011-09-02 Piotr Milos

We study the spatial fluctuations of transient creep deformation of materials as a function of time, both by Digital Image Correlation (DIC) measurements of paper samples and by numerical simulations of a crystal plasticity or discrete…

Materials Science · Physics 2015-05-28 Lasse Laurson , Jari Rosti , Juha Koivisto , Amandine Miksic , Mikko J. Alava

Almost all hydrodynamic accretion disk models parametrize viscosity with the dimensionless parameter alpha. There is no detailed model for alpha, so it is usually taken to be a constant. However, global simulations of magnetohydrodynamic…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Robert F. Penna , Aleksander Sadowski , Akshay K. Kulkarni , Ramesh Narayan

If a liquid is cooled rapidly to form a glass, its structural relaxation becomes retarded, producing a drastic increase in viscosity. In two dimensions, strong long-wavelength fluctuations persist, even at low temperature, making it…

Soft Condensed Matter · Physics 2019-12-25 Hayato Shiba , Takeshi Kawasaki , Kang Kim

(Abridged) We analyse the stability and evolution of power-law accretion disc models. These have midplane densities that follow radial power-laws, and have either temperature or entropy distributions that are power-law functions of…

Earth and Planetary Astrophysics · Physics 2015-06-11 Richard P. Nelson , Oliver Gressel , Orkan M. Umurhan

Multi-fractal scaling in the transition to the dissipative regime for fully-developed compressible turbulence is considered. The multi-fractal power law scaling behavior breaks down for very small length scales thanks to viscous effects.…

Fluid Dynamics · Physics 2010-01-07 B. K. Shivamoggi

The work presented here focuses on the role of zonal flows in the self-sustenance of gravito-turbulence in accretion discs. The numerical analysis is conducted using a bespoke pseudo-spectral code in fully compressible, non-linear…

Solar and Stellar Astrophysics · Physics 2019-11-01 Riccardo Vanon

We analyze the effects of the background velocity and the initial magnetic field correlations, and viscosities on the turbulent dynamo and the \alpha-effect. We calculate the \alpha-coefficients for arbitrary magnetic and fluid viscosities,…

Statistical Mechanics · Physics 2009-11-10 Abhik Basu

We extend the procedure outlined in [Basse, "Scaling of global properties of fluctuating and mean streamwise velocities in pipe flow: Characterization of a high Reynolds number transition region," Phys. Fluids Vol. 33, 065127 (2021)] to…

Fluid Dynamics · Physics 2021-12-15 Nils T. Basse

Here we report on the viscosity of eukaryotic living cells as a function of the time, and on the application of stochastic models to analyze its temporal fluctuations. The viscoelastic properties of NIH/3T3 fibroblastic cells are…

Soft Condensed Matter · Physics 2021-09-21 Claude L. Bostoen , Jean-François Berret

The possibility that some of the observed X-ray and optical variability in active galactic nuclei and galactic black hole candidates is produced in accretion disks through the development of a self-organized critical state is reconsidered.…

Astrophysics · Physics 2015-06-24 Ying Xiong , Paul J. Wiita , Gang Bao

We study the average shape of a fluctuation of a time series x(t), that is the average value <x(t)-x(0)>_T before x(t) first returns, at time T, to its initial value x(0). For large classes of stochastic processes we find that a scaling law…

Statistical Mechanics · Physics 2009-11-10 Andrea Baldassarri , Francesca Colaiori , Claudio Castellano

The classical dynamics of a particle that is driven by a rapidly oscillating potential (with frequency $\omega$) is studied. The motion is separated into a slow part and a fast part that oscillates around the slow part. The motion of the…

Chaotic Dynamics · Physics 2007-05-23 Saar Rahav , Eli Geva , Shmuel Fishman

The mathematical model of a real flexible elastic system with distributed and discrete parameters is considered. It is a partial differential equation with non-classical boundary conditions. Complexity of the boundary conditions results in…

Analysis of PDEs · Mathematics 2007-05-23 Olena V. Mul , Delfim F. M. Torres

We study general aspects of active motion with fluctuations in the speed and the direction of motion in two dimensions. We consider the case in which fluctuations in the speed are not correlated to fluctuations in the direction of motion,…

Biological Physics · Physics 2009-11-13 Fernando Peruani , Luis G. Morelli