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Related papers: Spectral Closure for the Linear Boltzmann-BGK Equa…

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Both the right and left eigenfunctions and eigenvalues of the linearized homogeneous Boltzmann equation for inelastic Maxwell molecules corresponding to the hydrodynamic modes are calculated. Also, some non-hydrodynamic modes are…

Statistical Mechanics · Physics 2015-05-18 J. J. Brey , M. I. Garcia de Soria , P. Maynar

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…

Solving the Bhatnagar-Gross-Krook (BGK) equation with a stochastic particle approach enables efficient and flexible simulations of flows in the transition regime, between continuum and free molecular flow. However, the usual first-order…

Fluid Dynamics · Physics 2024-12-02 Marcel Pfeiffer , Félix Garmirian , Tobias Ott

In this paper, we are interested in the Cauchy problem for the Boltzmann-BGK model for a general class of collision frequencies. We prove that the Boltzmann-BGK model linearized around a global Maxwellian admits a unique global smooth…

Analysis of PDEs · Mathematics 2015-05-20 Seok-Bae Yun

Nonlinear acoustics of wind instruments conducts to study unidimensional fluid flows. From physically relevant approximations that are modelized with the thin layer Navier Stokes equations, we propose a coupled model where perfect fluid…

Numerical Analysis · Mathematics 2010-06-16 Régis Msallam , François Dubois

We study a simplified Ericksen-Leslie system modeling the flow of nematic liquid crystals with partially free boundary conditions. It is a coupled system between the Navier-Stokes equation for the fluid velocity with a transported heat flow…

Analysis of PDEs · Mathematics 2023-03-22 Fanghua Lin , Yannick Sire , Juncheng Wei , Yifu Zhou

We propose a BGK-type kinetic model for relativistic reactive gas mixtures. This model serves as a computationally tractable yet physically consistent alternative to the corresponding Boltzmann equation. The relaxation operator is…

Analysis of PDEs · Mathematics 2025-09-03 Seung-Yeon Cho , Byung-Hoon Hwang , Myeong-Su Lee , Seok-Bae Yun

The non--static generalized Langevin equation and its corresponding Fokker--Planck equation for the position of a viscous fluid particle were solved in closed form for a time dependent external force. Its solution for a constant external…

Statistical Mechanics · Physics 2018-05-08 Wilmer Olivares-Rivas , Pedro J. Colmenares

The regularity of solutions to the Boltzmann equation is a fundamental problem in the kinetic theory. In this paper, the case with angular cut-off is investigated. It is shown that the macroscopic parts of solutions to the Boltzmann…

Analysis of PDEs · Mathematics 2016-01-07 Feimin Huang , Yong Wang

A new lattice Boltzmann (LB) model is introduced, based on a regularization of the pre-collision distribution functions in terms of the local density, velocity, and momentum flux tensor. The model dramatically improves the precision and…

Fluid Dynamics · Physics 2007-05-23 Jonas Latt , Bastien Chopard

The focus of the present study is the modified Buckley-Leverett (MBL) equation describing two-phase flow in porous media. The MBL equation differs from the classical Buckley-Leverett (BL) equation by including a balanced…

Numerical Analysis · Mathematics 2011-09-19 Ying Wang , Chiu-Yen Kao

In this paper we establish the local-in-time existence and uniqueness of strong solutions to the free boundary problem of the full compressible Navier-Stokes equations in three-dimensional space. The vanishing density and temperature…

Analysis of PDEs · Mathematics 2018-04-11 Xin Liu , Yuan Yuan

A challenging problem in solving the Boltzmann equation numerically is that the velocity space is approximated by a finite region. Therefore, most methods are based on a truncation technique and the computational cost is then very high if…

Analysis of PDEs · Mathematics 2013-06-14 Minh-Binh Tran

We apply pseudo-spectral methods to integrate functional flow equations with high accuracy, extending earlier work on functional fixed point equations \cite{Borchardt:2015rxa}. The advantages of our method are illustrated with the help of…

High Energy Physics - Theory · Physics 2016-07-27 Julia Borchardt , Benjamin Knorr

We demonstrate that the Chapman-Enskog series is locally equivalent to the exact spectral closure defined on slow kinetic eigenmodes in the limit of vanishing Knudsen number. We further show that the Chapman-Enskog series diverges…

Mathematical Physics · Physics 2025-06-25 Florian Kogelbauer , Ilya Karlin

The local balance equations for the density, momentum, and energy of a dilute gas of elastic or inelastic hard spheres, strongly confined between two parallel hard plates are obtained. The starting point is a Boltzmann-like kinetic…

Statistical Mechanics · Physics 2020-04-22 J. Javier Brey , P. Maynar , M. I. García de Soria

It is well known that the full compressible Navier-Stokes equations can be deduced via the Chapman-Enskog expansion from the Boltzmann equation as the first-order correction to the Euler equations with viscosity and heat-conductivity…

Analysis of PDEs · Mathematics 2020-08-21 Renjun Duan , Shuangqian Liu

In this paper, we propose a lattice Boltzmann (LB) model to solve the coupled Cahn-Hilliard-Navier-Stokes equations. Differently from previous efforts, the LB equation for the fluid velocity is decomposed in a space of non-orthogonal…

Fluid Dynamics · Physics 2018-04-02 Alessandro De Rosis , Shimpei Saito , Akiko Kaneko , Yutaka Abe

A deterministic method is proposed for solving the Boltzmann equation. The method employs a Galerkin discretization of the velocity space and adopts, as trial and test functions, the collocation basis functions based on weights and roots of…

Computational Physics · Physics 2013-11-19 Gian Pietro Ghiroldi , Livio Gibelli

In a recent paper [1] the scattering and transport of excess electrons in liquid argon in the hydrodynamic regime was investigated, generalizing the seminal works of Lekner and Cohen [2,3] with modern scattering theory techniques and…

Computational Physics · Physics 2017-10-02 G. J. Boyle , D. G. Cocks , W. J. Tattersall , R. P. McEachran , R. D. White