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We study anisotropic fluid dynamics derived from the Boltzmann equation based on a particular choice for the anisotropic distribution function within a boost-invariant expansion of the fluid in one spatial dimension. In order to close the…

Nuclear Theory · Physics 2018-03-14 H. Niemi , E. Molnár , D. H. Rischke

We derive a system of moment-based dynamical equations that describe the 1+1d space-time evolution of a cylindrically symmetric massive gas undergoing boost-invariant longitudinal expansion. Extending previous work, we introduce an explicit…

High Energy Physics - Phenomenology · Physics 2014-07-30 Mohammad Nopoush , Radoslaw Ryblewski , Michael Strickland

The higher-order gas-kinetic scheme for solving the Navier-Stokes equations has been studied in recent years. In addition to the use of higher-order reconstruction techniques, many terms are used in the Taylor expansion of the gas…

Computational Physics · Physics 2017-04-05 Guangzhao Zhou , Kun Xu , Feng Liu

We study a three-wave truncation of a recently proposed damped/forced high-order nonlinear Schr\"odinger equation for deep-water gravity waves under the effect of wind and viscosity. The evolution of the norm (wave-action) and spectral mean…

Fluid Dynamics · Physics 2018-01-08 Andrea Armaroli , Debbie Eeltink , Maura Brunetti , Jérôme Kasparian

We study a one-dimensional equation arising in the multiscale modeling of some non-Newtonian fluids. At a given shear rate, the equation provides the instantaneous mesoscopic response of the fluid, allowing to compute the corresponding…

Mathematical Physics · Physics 2014-04-29 David Benoit , Claude Le Bris , Tony Lelièvre

We present a relativistic Shakhov-type generalization of the Anderson-Witting relaxation time model for the Boltzmann collision integral to modify the ratio of momentum diffusivity to thermal diffusivity. This is achieved by modifying the…

Nuclear Theory · Physics 2024-09-10 Victor E. Ambruş , Etele Molnár

We derive an analytic expression for the shear viscosity of an ultra-relativistic gas in presence of both elastic $2\to 2$ and inelastic $2\leftrightarrow 3$ processes with isotropic differential cross sections. The derivation is based on…

High Energy Physics - Theory · Physics 2014-04-28 Andrej El , Francesco Lauciello , Christian Wesp , Ioannis Bouras , Zhe Xu , Carsten Greiner

We study solution techniques for an evolution equation involving second order derivative in time and the spectral fractional powers, of order $s \in (0,1)$, of symmetric, coercive, linear, elliptic, second-order operators in bounded domains…

Numerical Analysis · Mathematics 2018-06-18 Lehel Banjai , Enrique Otarola

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 solve the one-dimensional boost-invariant kinetic equation for a relativistic massive system with the collision term treated in the relaxation time approximation. The result is an exact integral equation which can be solved numerically…

High Energy Physics - Phenomenology · Physics 2014-05-22 Wojciech Florkowski , Ewa Maksymiuk , Radoslaw Ryblewski , Michael Strickland

In this contribution, a new class of lattice Boltzmann schemes is introduced and studied. These schemes are presented in a framework that generalizes the multiple relaxation times method of d'Humi\`eres. They extend also the Geier's…

Numerical Analysis · Mathematics 2015-01-27 François Dubois , Tony Fevrier , Benjamin Graille

We present new analytic solutions to the relativistic Boltzmann equation within the relaxation time approximation. We first obtain spherically expanding solutions which are the kinetic counterparts of the exact solutions of the…

High Energy Physics - Theory · Physics 2015-04-22 Yoshitaka Hatta , Mauricio Martinez , Bo-Wen Xiao

We derive equations for fluid dynamics from a non-extensive Boltzmann transport equation consistent with Tsallis' non-extensive entropy formula. We evaluate transport coefficients employing the relaxation time approximation and investigate…

Nuclear Theory · Physics 2015-05-30 T. S. Biro , E. Molnar

We compute the hydrodynamic relaxation times $\tau_\pi$ and $\tau_j$ for hot QCD at next-to-leading order in the coupling with kinetic theory. We show that certain dimensionless ratios of second-order to first-order transport coefficients…

High Energy Physics - Phenomenology · Physics 2018-08-02 Jacopo Ghiglieri , Guy D. Moore , Derek Teaney

We consider a kinetic model whose evolution is described by a Boltzmann-like equation for the one-particle phase space distribution $f(x,v,t)$. There are hard-sphere collisions between the particles as well as collisions with randomly fixed…

Mathematical Physics · Physics 2020-01-08 Raffaele Esposito , Pedro G. Garrido , Joel L. Lebowitz , Rossana Marra

We revisit the issue of relaxation to thermal equilibrium in the so-called "sheet model", i.e., particles in one dimension interacting by attractive forces independent of their separation. We show that this relaxation may be very clearly…

Statistical Mechanics · Physics 2010-11-03 Michael Joyce , Tirawut Worrakitpoonpon

A relaxed notion of displacement convexity is defined and used to establish short time existence and uniqueness of Wasserstein gradient flows for higher order energy functionals. As an application, local and global well-posedness of…

Analysis of PDEs · Mathematics 2012-01-18 Ehsan Kamalinejad

In this paper, we propose a method of solving the viscous hydrodynamics order by order in a derivative expansion. In such a method, the zero-order solution is just one of the ideal hydrodynamics. All the other higher order corrections…

Nuclear Theory · Physics 2015-10-21 Jian-Hua Gao , Shi Pu

We present the perturbative solution of the multicomponent Boltzmann kinetic equation based on the set of observables including the hydrodynamic velocity and temperature for each component. The solution is obtained by modifying the formal…

Statistical Mechanics · Physics 2008-01-23 S. V. Savenko , E. A. J. F. Peters , P. J. A. M. Kerkhof

We derive exact equations governing the large-scale dynamics of hard rods, including diffusive effects that go beyond ballistic transport. Diffusive corrections are the first-order terms in the hydrodynamic gradient expansion and we obtain…

Statistical Mechanics · Physics 2026-02-18 Friedrich Hübner , Leonardo Biagetti , Jacopo De Nardis , Benjamin Doyon