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In this paper we provide a quantum field theoretical study on the shear and bulk relaxation times. First, we find Kubo formulas for the shear and the bulk relaxation times, respectively. They are found by examining response functions of the…

Nuclear Theory · Physics 2017-08-16 Alina Czajka , Sangyong Jeon

Spatial non-locality of space-fractional viscoelastic equations of motion is studied. Relaxation effects are accounted for by replacing second-order time derivatives by lower-order fractional derivatives and their generalizations. It is…

Mathematical Physics · Physics 2015-06-03 Andrzej Hanyga , Malgorzata Seredynska

We present simulations of stochastic fluid dynamics in the vicinity of a critical endpoint belonging to the universality class of the Ising model. This study is motivated by the challenge of modeling the dynamics of critical fluctuations…

Nuclear Theory · Physics 2024-07-23 Chandrodoy Chattopadhyay , Josh Ott , Thomas Schaefer , Vladimir V. Skokov

We present a new approach to find accurate solutions to the Poisson equation, as obtained from the steady-state limit of a diffusion equation with strong source terms. For this purpose, we start from Boltzmann's kinetic theory and…

Computational Physics · Physics 2015-04-23 M. Mendoza , S. Succi , H. J. Herrmann

Several hydrodynamic models the atomic Bose-Einstein condensate beyond the mean-field approximation are discussed together from one point of view. All these models are derived from microscopic quantum description. The derivation is made…

Quantum Gases · Physics 2021-05-05 Pavel A. Andreev

We describe an asymptotic procedure for deriving continuum equations from the kinetic theory of a simple gas. As in the works of Hilbert, of Chapman and of Enskog, we expand in the mean flight time of the constituent particles of the gas,…

Astrophysics · Physics 2009-11-06 Xinzhong Chen , Hongling Rao , Edward A. Spiegel

Thermodynamic nonequilibrium effects play a central role in momentum and energy transport in compressible flows. In conventional BGK kinetic models, the relaxation time $\tau$ is taken as a constant, which neglects the dependence of the…

Fluid Dynamics · Physics 2026-05-19 Demei Li , Zhongyi He , Huilin Lai , Yanbiao Gan , Hailong Liu , Pengfei Lin

Relaxation in glasses is often approximated by a stretched-exponential form: $f(t) = A \exp [-(t/\tau)^{\beta}]$. Here, we show that the relaxation in a model of sheared non-Brownian suspensions developed by Cort\'e et al. [Nature Phys. 4,…

Soft Condensed Matter · Physics 2017-02-02 Joseph D. Paulsen , Sidney R. Nagel

A fourth-order nonlinear evolution equation is derived from a microscopic model for surface diffusion, namely, the continuum solid-on-solid model. We use the method developed by Varadhan for the computation of hydrodynamic scaling limit of…

Probability · Mathematics 2007-05-23 Anamaria Savu

In this work, closure of the Boltzmann--BGK moment hierarchy is accomplished via projection of the distribution function $f$ onto a space $\mathbb{H}^{N}$ spanned by $N$-order Hermite polynomials. While successive order approximations…

Fluid Dynamics · Physics 2010-02-15 Carlos E. Colosqui

In this paper, we develop and characterize the fully dissipative Lattice Boltzmann method for ultra-relativistic fluids in two dimensions using three equilibrium distribution functions: Maxwell-J\"uttner, Fermi-Dirac and Bose-Einstein. Our…

Fluid Dynamics · Physics 2018-05-02 Rodrigo C. V. Coelho , Miller Mendoza , Mauro M. Doria , Hans J. Herrmann

We formulate a perturbative approximation to gravitational instability, based on Lagrangian hydrodynamics in Newtonian cosmology. We take account of `pressure' effect of fluid, which is kinematically caused by velocity dispersion, to aim…

Astrophysics · Physics 2009-11-07 Masaaki Morita , Takayuki Tatekawa

In this paper we generalize the construction of locally boosted black brane space time to higher derivative gravities. We consider the Gauss-Bonnet term (with coefficient $\alpha'$) as a toy example. We find the solution to the $\alpha'$…

High Energy Physics - Theory · Physics 2014-11-18 Suvankar Dutta

We present exact solutions of the (0+1)-dimensional kinetic equation for a massive gas in the relaxation time approximation. At first, we analyse the case of classical statistics and argue that the traditional second-order hydrodynamics…

High Energy Physics - Phenomenology · Physics 2015-06-11 Ewa Maksymiuk

Lattice Boltzmann models are briefly introduced together with references to methods used to predict their ability for simulations of systems described by partial differential equations that are first order in time and low order in space…

Numerical Analysis · Mathematics 2024-11-15 Pierre Lallemand , François Dubois , Li-shi Luo

We derive the hydrodynamic limit of a kinetic equation where the interactions in velocity are modelled by a linear operator (Fokker-Planck or Linear Boltzmann) and the force in the Vlasov term is a stochastic process with high amplitude and…

Analysis of PDEs · Mathematics 2020-03-23 Arnaud Debussche , Julien Vovelle

Considering the rheology of two-dimensional soft suspensions above the jamming density, we derive a tensorial constitutive model from the microscopic particle dynamics. Starting from the equation governing the $N$-particle distribution, we…

Soft Condensed Matter · Physics 2022-03-15 Nicolas Cuny , Romain Mari , Eric Bertin

We analyze the representation of viscous stresses in the one-fluid formulation of the two-phase Navier-Stokes equations, the model on which all computational approaches making use of a fixed mesh to discretize the flow field are grounded.…

Fluid Dynamics · Physics 2025-06-06 Jacques Magnaudet , Hadrien Bruhier , Samuel Mer , Thomas Bonometti

We apply the post-quasi--static approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of anisotropic non-adiabatic radiating and dissipative distributions in General Relativity.…

General Relativity and Quantum Cosmology · Physics 2010-05-25 C. Peralta , L. Rosales , B. Rodrí guez-Mueller , W. Barreto

We apply a quasistatic nonlinear model for nonsimple viscoelastic materials at a finite-strain setting in the Kelvin's-Voigt's rheology to derive a viscoelastic plate model of von K\'arm\'an type. We start from time-discrete solutions to a…

Analysis of PDEs · Mathematics 2020-07-15 Manuel Friedrich , Martin Kružík
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