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We present the derivation of a novel third-order hydrodynamic evolution equation for shear stress tensor from kinetic theory. Boltzmann equation with relaxation time approximation for the collision term is solved iteratively using…

Nuclear Theory · Physics 2013-09-02 Amaresh Jaiswal

In the present paper, we concern the hydrodynamic limit of Boltzmann equation with specular reflection boundary condition in a two-dimensional disk to the compressible Euler equations. Due to the non-zero curvature and non-zero tangential…

Analysis of PDEs · Mathematics 2025-04-22 Feimin Huang , Jing Ouyang , Yong Wang

We present an exact solution of the relativistic Boltzmann equation for a system undergoing boost-invariant longitudinal and azimuthally symmetric transverse flow ("Gubser flow"). The resulting exact non-equilibrium dynamics is compared to…

High Energy Physics - Phenomenology · Physics 2014-11-17 Gabriel S. Denicol , Ulrich W. Heinz , Mauricio Martinez , Jorge Noronha , Michael Strickland

In the Hermite-expansion-based multiple-relaxation-time lattice Boltzmann (LB) model [Shan & Chen, Int. J. Mod. Phys. C, 18, 635, (2007)], a separate relaxation time is assigned to each of the tensorial moments of the collision term. Here…

Computational Physics · Physics 2021-05-05 Xuhui Li , Xiaowen Shan

A foundational question in relativistic fluid mechanics concerns the properties of the hydrodynamic gradient expansion at large orders. We establish the precise conditions under which this gradient expansion diverges for a broad class of…

High Energy Physics - Theory · Physics 2021-09-08 Michal P. Heller , Alexandre Serantes , Michał Spaliński , Viktor Svensson , Benjamin Withers

We obtain equations of motion for the boost-invariant expansion of a system of chiral particles. Our analysis is based on the Boltzmann equation for left- and right-handed massless particles in the relaxation time approximation. We assume…

High Energy Physics - Phenomenology · Physics 2024-02-15 Nora Weickgenannt , Jean-Paul Blaizot

The Goldstein-Taylor equations can be thought of as a simplified version of a BGK system, where the velocity variable is constricted to a discrete set of values. It is intimately related to turbulent fluid motion and the telegrapher's…

Analysis of PDEs · Mathematics 2021-03-17 Anton Arnold , Amit Einav , Beatrice Signorello , Tobias Wöhrer

Consider 3D Boltzmann equation in convex domains with diffusive-reflection boundary condition. We study the hydrodynamic limits as the Knudsen number and Strouhal number $\epsilon\rightarrow 0^+$. Using the Hilbert expansion, we rigorously…

Analysis of PDEs · Mathematics 2020-10-02 Lei Wu , Zhimeng Ouyang

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

The hydrodynamic limit for the Boltzmann equation is studied in the case when the limit system, that is, the system of Euler equations contains contact discontinuities. When suitable initial data is chosen to avoid the initial layer, we…

Analysis of PDEs · Mathematics 2015-05-13 Feimin Huang , Yi Wang , Tong Yang

This paper proposes a thorough theoretical analysis of Stochastic Gradient Descent (SGD) with non-increasing step sizes. First, we show that the recursion defining SGD can be provably approximated by solutions of a time inhomogeneous…

Optimization and Control · Mathematics 2021-02-02 Xavier Fontaine , Valentin De Bortoli , Alain Durmus

Here we derive the relativistic resistive dissipative second-order magnetohydrodynamic evolution equations using the Boltzmann equation, thus extending our work from the previous paper…

Nuclear Theory · Physics 2021-09-27 Ankit Kumar Panda , Ashutosh Dash , Rajesh Biswas , Victor Roy

This paper addresses a new class of generalized Bolza problems governed by nonconvex integro-differential inclusions with endpoint constraints on trajectories, where the integral terms are given in the general (with time-dependent…

Optimization and Control · Mathematics 2024-10-07 Abderrahim Bouach , Tahar Haddad , Boris S. Mordukhovich

Gradient algorithms are classical in adaptive control and parameter estimation. For instantaneous quadratic cost functions they lead to a linear time-varying dynamic system that converges exponentially under persistence of excitation…

Optimization and Control · Mathematics 2020-10-06 Juan G. Rueda-Escobedo , Jaime A. Moreno

We consider a class of nonlinear Boltzmann equations describing return to thermal equilibrium in a gas of colliding particles suspended in a thermal medium. We study solutions in the space $L^{1}(\mathbb{R}^{3}\times \mathbb{T}^3).$ Special…

Analysis of PDEs · Mathematics 2016-12-28 Juerg Froehlich , Zhou Gang

I demonstrate that the concept of a non-equilibrium attractor can be extended beyond the lowest-order moments typically considered in hydrodynamic treatments. Using a previously obtained exact solution to the relaxation-time approximation…

Nuclear Theory · Physics 2022-01-12 Michael Strickland

We use a set of simple angular moments to solve the Boltzmann equation in the relaxation time approximation for a boost invariant longitudinally expanding gluonic plasma. The transition from the free streaming regime at early time to the…

Nuclear Theory · Physics 2020-01-08 Jean-Paul Blaizot , Li Yan

A type of discrete Boltzmann model for simulating shallow water flows is derived by using the Hermite expansion approach. Through analytical analysis, we study the impact of truncating distribution function and discretizing particle…

Fluid Dynamics · Physics 2018-07-16 Jianping Meng , Xiao-Jun Gu , David R Emerson , Yong Peng , Jianmin Zhang

A simplified relativistic kinetic theory for gases with internal degrees of freedom, based on a BGK-type collision term, is considered. First the Boltzmann equation is rewritten in tetrad form and then thermal coefficients are determined to…

General Relativity and Quantum Cosmology · Physics 2026-04-13 Philip Semrén , Michael Bradley , João M. S. Oliveira , M. Piedade Machado Ramos

One-dimensional self-gravitating systems admit genuine thermodynamical equilibria. For systems with strictly monotonic orbital frequency profile, the Landau and Balescu-Lenard theories predict a relaxation time scaling linearly with the…

Astrophysics of Galaxies · Physics 2026-03-13 Kerwann Tep , Jean-Baptiste Fouvry , Christophe Pichon