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Bernstein-Kruskal-Greene (or BGK) modes are ubiquitous nonlinear solutions for the 1D electrostatic Vlasov equation, with the particle distribution function $f$ given as a function of the particle energy. Here, we consider other solutions…

Plasma Physics · Physics 2019-10-22 Benjamin J. Q. Woods

The discrete effect on the boundary condition has been a fundamental topic for the lattice Boltzmann method in simulating heat and mass transfer problems. In previous works based on the halfway anti-bounce-back (ABB) boundary condition for…

Computational Physics · Physics 2020-02-19 Liang Wang , Xuhui Meng , Hao-Chi Wu , Tian-Hu Wang , Gui Lu

A thermal lattice Boltzmann model is constructed on the basis of the ellipsoidal statistical Bhatnagar-Gross-Krook (ES-BGK) collision operator via the Hermite moment representation. The resulting lattice ES-BGK model uses a single…

To simulate non-equilibrium compressible flows, a new discrete Boltzmann model, discrete Ellipsoidal Statistical(ES)-BGK model, is proposed. Compared with the original discrete BGK model, the discrete ES-BGK has a flexible Prandtl number.…

Fluid Dynamics · Physics 2018-03-08 Yudong Zhang , Aiguo Xu , Guangcai Zhang , Zhihua Chen , Pei Wang

We propose a kinetic relaxation-model to describe a generation-recombination reaction of two species. The decay to equilibrium is studied by two recent methods for proving hypocoercivity of the linearized equations. Exponential decay of…

Analysis of PDEs · Mathematics 2015-03-20 Lukas Neumann , Christian Schmeiser

The lattice Bhatnagar-Gross-Krook (LBGK) model has become the most popular one in the lattice Boltzmann method for simulating the convection heat transfer in porous media. However, the LBGK model generally suffers from numerical instability…

Computational Physics · Physics 2015-05-13 Liang Wang , Jianchun Mi , Zhaoli Guo

We consider the neural sparse representation to solve Boltzmann equation with BGK and quadratic collision model, where a network-based ansatz that can approximate the distribution function with extremely high efficiency is proposed.…

Numerical Analysis · Mathematics 2023-02-21 Zhengyi Li , Yanli Wang , Hongsheng Liu , Zidong Wang , Bin Dong

Partial differential equations (p.d.e) equipped of spatial derivatives of fractional order capture anomalous transport behaviors observed in diverse fields of Science. A number of numerical methods approximate their solutions in dimension…

Computational Physics · Physics 2018-08-21 Alain Cartalade , Amina Younsi , Marie-Christine Néel

We study convergence to equilibrium of the linear relaxation Boltzmann (also known as linear BGK) and the linear Boltzmann equations either on the torus $(x,v) \in \mathbb{T}^d \times \mathbb{R}^d$ or on the whole space $(x,v) \in…

Analysis of PDEs · Mathematics 2020-11-10 José A. Cañizo , Chuqi Cao , Josephine Evans , Havva Yoldaş

The Borgnakke-Larsen model, widely used in rarefied flow predictions, serves as the mainstream energy-exchange kernel for polyatomic gases. However, it lacks integrability and does not guarantee detailed balance, limiting theoretical…

Computational Physics · Physics 2026-04-02 Sha Liu , Ningchao Ding , Ming Fang , Hao Jin , Rui Zhang , Congshan Zhuo , Chengwen Zhong

The paper presents a solution to the Boltzmann kinetic equation based on the construction of its discrete conservative model. Discrete analogue of the collision integral is presented as a contraction of a tensor, which is independent from…

Statistical Mechanics · Physics 2017-07-04 George Arabuli

We prove the existence of non-hydrodynamic solutions to the linear density-dependent BGK equation in $d$ dimensions. Specifically, we show the existence of an initial condition for any Knudsen number $\tau$ for which the dissipation rate of…

Analysis of PDEs · Mathematics 2026-01-22 Florian Kogelbauer

We study the dynamics of relaxation and thermalization in an exactly solvable model of a particle interacting with a harmonic oscillator bath. Our goal is to understand the effects of non-Markovian processes on the relaxational dynamics and…

Condensed Matter · Physics 2009-10-31 S. M. Alamoudi , D. Boyanovsky , H. J. de Vega

We establish the existence and uniqueness of mild solutions for the polyatomic ellipsoidal BGK model, which is a relaxation type kinetic model describing the evolution of polyatomic gaseous system at the mesoscopic level.

Analysis of PDEs · Mathematics 2017-08-09 Sa Jun Park , Seok-Bae Yun

The over-relaxation approach is an alternative to the Jin-Xin relaxation method (Jin and Xin [1]) in order to apply the equilibrium source term in a more precise way (Coulette et al. [2, 3]). This is also a key ingredient of the…

Analysis of PDEs · Mathematics 2018-07-17 Florence Drui , Emmanuel Franck , Philippe Helluy , Laurent Navoret

We propose a new kinetic BGK-type model for a mixture of four monatomic gases, undergoing a bimolecular and reversible chemical reaction. The elastic and reactive interactions are described separately by distinct relaxation terms and the…

Statistical Mechanics · Physics 2026-01-07 Giorgio Martalò , Ana Jacinta Soares , Romina Travaglini

We present a systematic account of recent developments of the relativistic Lattice Boltzmann method (RLBM) for dissipative hydrodynamics. We describe in full detail a unified, compact and dimension-independent procedure to design…

High Energy Physics - Lattice · Physics 2020-05-29 A. Gabbana , D. Simeoni , S. Succi , R. Tripiccione

We provide a framework to extend the relative entropy method to a class of diffusive relaxation systems with discrete velocities. The methodology is detailed in the toy case of the 1D Jin-Xin model under the diffusive scaling, and provides…

Analysis of PDEs · Mathematics 2020-01-22 Roberta Bianchini

We derive an analytical connection between kinetic relaxation rate and bulk viscosity of a relativistic fluid in d spatial dimensions, all the way from the ultra-relativistic down to the near non-relativistic regime. Our derivation is based…

Fluid Dynamics · Physics 2020-06-23 A. Gabbana , D. Simeoni , S. Succi , R. Tripiccione

We present a more refined version of rational extended thermodynamics of rarefied polyatomic gases in which molecular rotational and vibrational relaxation processes are treated individually. In this case we need a triple hierarchy of the…

Statistical Mechanics · Physics 2017-10-25 Takashi Arima , Tommaso Ruggeri , Masaru Sugiyama