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Chaotic motion in time of a number of macroscopic systems has been analyzed, in the framework of scale relativity, as motion in a fractal space with topological dimension 3 and geodesics with fractal dimension 2. The motion equation is then…

General Physics · Physics 2009-11-16 Marie-Noëlle Célérier

The importance of roughness in the modeling of granular gases has been increasingly considered in recent years. In this paper, a freely evolving homogeneous granular gas of inelastic and rough hard disks or spheres is studied under the…

Soft Condensed Matter · Physics 2023-07-25 Alberto Megías , Andrés Santos

A surprising exact result for the Einstein Field Equations is that if pressure-free matter is moving in a shear-free way, then it must be either expansion-free or rotation-free. It has been suggested this result is also true for any…

General Relativity and Quantum Cosmology · Physics 2012-02-20 Anne Marie Nzioki , Rituparno Goswami , Peter K. S. Dunsby , George F. R. Ellis

We study the dynamics of the noncommutative fuid in the Snyder space perturbatively at the first order in powers of the noncommutative parameter. The linearized noncommutative fluid dynamics is described by a system of coupled linear…

High Energy Physics - Theory · Physics 2016-11-26 M. C. B. Abdalla , L. Holender , M. A. Santos , I. V. Vancea

We propose a simple stochastic model of cascading transport in wave number space to clarify the origin of intermittent behavior of fully-developed fluid turbulence. In spite of lack of nonlinearity and viscosity the model gives non-Gaussian…

chao-dyn · Physics 2008-02-03 Hideki Takayasu , Y-h. Taguchi , Tomoo Katsuyama

We present a novel method to investigate the dynamics of a single semiflexible polymer, subject to anisotropic friction in a viscous fluid. In contrast to previous approaches, we do not rely on a discrete bead-rod model, but introduce a…

Biomolecules · Quantitative Biology 2009-11-13 Tobias Munk , Oskar Hallatschek , Chris H. Wiggins , Erwin Frey

Numerical evidence of non-diffusive transport in three-dimensional, resistive pressure-gradient-driven plasma turbulence is presented. It is shown that the probability density function (pdf) of test particles' radial displacements is…

Plasma Physics · Physics 2009-11-10 D. del-Castillo-Negrete , B. A. Carreras , V. E. Lynch

We study the non-boost-invariant evolution of a quark-gluon plasma subject to large early-time momentum-space anisotropies. Rather than using the canonical hydrodynamical expansion of the distribution function around an isotropic…

Nuclear Theory · Physics 2014-01-08 Mauricio Martinez , Michael Strickland

We determine the energy-momentum tensor of non-perfect fluids in thermodynamic equilibrium. To this end, we derive the constitutive equations for energy density, isotropic and anisotropic pressure as well as for heat-flux from the…

General Relativity and Quantum Cosmology · Physics 2016-04-26 Konrad Schatz , Horst-Heino von Borzeszkowski , Thoralf Chrobok

It is shown that unlike the perfect fluid case, anisotropic fluids (principal stresses unequal) may be geodesic, without this implying the vanishing of (spatial) pressure gradients. Then the condition of vanishing four acceleration is…

General Relativity and Quantum Cosmology · Physics 2009-11-07 L. Herrera , J. Martin , J. Ospino

We test the validity of Isaacson's formula which states that high frequency and low amplitude gravitational waves behave as a radiation fluid on average. For this purpose, we numerically construct a solution of the vacuum Einstein equations…

General Relativity and Quantum Cosmology · Physics 2015-08-26 Taishi Ikeda , Chul-Moon Yoo , Yasusada Nambu

We present a lattice-based numerical method to describe the non equilibrium behavior of a simple fluid under non-uniform spatial conditions. The evolution equation for the one-particle phase-space distribution function is derived starting…

Statistical Mechanics · Physics 2009-11-13 S. Melchionna , U. Marini Bettolo Marconi

Spherically symmetric expansionfree distributions are systematically studied. The whole set of field equations and junction conditions are presented for a general distribution of dissipative anisotropic fluid (principal stresses unequal),…

General Relativity and Quantum Cosmology · Physics 2008-11-26 L. Herrera , N. O. Santos , A. Wang

We consider the physical setup of a three-dimensional fluid-structure interaction problem. A viscous compressible gas or liquid interacts with a nonlinear, visco-elastic, three-dimensional bulk solid. The latter is described by a hyperbolic…

Analysis of PDEs · Mathematics 2021-08-09 Dominic Breit , Malte Kampschulte , Sebastian Schwarzacher

The dissipative dynamics of an expanding massless gas with constant cross section in a spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe is studied. The mathematical problem of solving the full nonlinear relativistic…

High Energy Physics - Phenomenology · Physics 2016-12-14 D. Bazow , G. S. Denicol , U. Heinz , M. Martinez , J. Noronha

We investigate the flow of various non-Newtonian fluids through three-dimensional disordered porous media by direct numerical simulation of momentum transport and continuity equations. Remarkably, our results for power-law (PL) fluids…

Fluid Dynamics · Physics 2009-11-09 Apiano F. Morais , Hansjoerg Seybold , Hans J. Herrmann , José S. Andrade

Sound wave propagation in a relativistic perfect fluid with a non-homogeneous isentropic flow is studied in terms of acoustic geometry. The sound wave equation turns out to be equivalent to the equation of motion for a massless scalar field…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Neven Bilic

We formulate non-relativistic classical and quantum mechanics in the non-commutative two dimensional plane. The approach we use is based on the Galilei group, where the non-commutativity is seen as a central extension upon identification of…

Mathematical Physics · Physics 2007-05-23 C. A. Vaquera-Araujo , J. L. Lucio M

According to a traditional point of view Boltzmann entropy is intimately related to linear Fokker-Planck equations (Smoluchowski, Klein-Kramers, and Rayleigh equations) that describe a well-known nonequilibrium phenomenon: (normal) Brownian…

General Physics · Physics 2017-01-11 A. O. Bolivar

In this paper we investigate the Quantum Brownian motion of a point particle induced by quantum vacuum fluctuations of a massless scalar field in (3 + 1)-dimensional Minkowski spacetime with distinct conditions (Dirichlet, Neumann, mixed…

High Energy Physics - Theory · Physics 2023-05-10 Éwerton J. B. Ferreira , Eliza M. B. Guedes , Herondy F. Santana Mota