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Related papers: Time-dependent Regularized 13-Moment Equations wit…

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We develop the steady-state regularized 13-moment equations in the linear regime for rarefied gas dynamics with general collision models. For small Knudsen numbers, the model is accurate up to the super-Burnett order, and the resulting…

Fluid Dynamics · Physics 2023-03-14 Zhenning Cai , Manuel Torrilhon , Siyao Yang

This paper establishes the global well-posedness of the linearized regularized 13-moment (R13) equations for rarefied gas flows. We first derive an entropy inequality for the system on bounded domains subject to Onsager boundary conditions.…

Analysis of PDEs · Mathematics 2026-05-20 Shuang Hu , Bo Lin , Huini Liu , Zhenning Cai

We propose a systematic methodology to derive the regularized thirteen-moment equations in the rarefied gas dynamics for a general class of linearized collision models. Detailed expressions of the moment equations are written down for all…

Fluid Dynamics · Physics 2020-05-13 Zhenning Cai , Yanli Wang

This paper presents a general framework for constructing reduced models that approximate the Boltzmann equation with arbitrary orders of accuracy in terms of the Knudsen number $\mathit{Kn}$, applicable to general collision models in…

Mathematical Physics · Physics 2025-05-19 Zhenning Cai , Ruo Li , Yixiao Lu , Yanli Wang

We propose a well-posed Maxwell-type boundary condition for the linear moment system in half-space. As a reduction of the Boltzmann equation, the moment equations are available to model Knudsen layers near a solid wall, where proper…

Analysis of PDEs · Mathematics 2023-01-31 Ruo Li , Yichen Yang

In this paper, we finally prove the well-posedness of the linearized R13 moment model, which describes, e.g., rarefied gas flows. As an extension of the classical fluid equations, moment models are robust and have been frequently used, yet…

Analysis of PDEs · Mathematics 2026-04-27 Peter Lewintan , Lambert Theisen , Manuel Torrilhon

Inspired by a recent hyperbolic regularization of Burnett's hydrodynamic equations [A. Bobylev, J. Stat. Phys. 124, 371 (2006)], we introduce a method to derive hyperbolic equations of linear hydrodynamics to any desired accuracy in Knudsen…

Statistical Mechanics · Physics 2007-06-13 M. Colangeli , I. V. Karlin , M. Kroger

For any regularity exponent $\beta<\frac 12$, we construct non-conservative weak solutions to the 3D incompressible Euler equations in the class $C^0_t (H^{\beta} \cap L^{\frac{1}{(1-2\beta)}})$. By interpolation, such solutions belong to…

Analysis of PDEs · Mathematics 2023-06-28 Matthew Novack , Vlad Vicol

We use guiding principles from nonequilibrium thermodynamics to develop an admissible set of 13 moment equations for rarefied gas flows. The main benefits of our thermodynamic approach are an explicit entropy expression fulfilling an $H$…

Statistical Mechanics · Physics 2010-11-10 Hans Christian Öttinger

We model the Knudsen layer in Kramers' problem by linearized high order hyperbolic moment system. Due to the hyperbolicity, the boundary conditions of the moment system is properly reduced from the kinetic boundary condition. For Kramers'…

Numerical Analysis · Mathematics 2017-04-20 Yuwei Fan , Jun Li , Ruo Li , Zhonghua Qiao

Grad's moment models for Boltzmann equation were recently regularized to globally hyperbolic systems, and thus the regularized models attain local well-posedness for Cauchy data. The hyperbolic regularization is only related to the…

Mathematical Physics · Physics 2017-03-24 Yana Di , Yuwei Fan , Ruo Li , Lingchao Zheng

In the Chapman & Enskog version of the Burnett equations the two time derivatives in the pressure tensor and heat current are replaced by spatial derivatives using the equations to zero order in the Knudsen number. Bobylev showed that the…

Statistical Mechanics · Physics 2007-05-23 Lars H. Söderholm

This work concerns with boundary conditions (BCs) of the linearized moment system for rarefied gases. As the Knudsen number is sufficiently small, we analyze the boundary-layer behaviors of the moment system by resorting to a three-scale…

Analysis of PDEs · Mathematics 2023-06-14 Ruo Li , Yichen Yang , Yizhou Zhou

Any numerical method fails to provide us with acceptable results if not equipped with appropriate boundary conditions. Catering to more realistic applications, in the present article we have extended the work done on the one plus one…

Numerical Analysis · Mathematics 2017-04-17 Neeraj Sarna

Half-space problems in the kinetic theory of gases are of great importance in the study of the asymptotic behavior of solutions of boundary value problems for the Boltzmann equation for small Knudsen numbers. In this work a generally…

Analysis of PDEs · Mathematics 2024-01-09 Niclas Bernhoff

We propose a new Nitsche-type approach for weak enforcement of normal velocity boundary conditions for a Lagrangian discretization of the compressible shock-hydrodynamics equations using high-order finite elements on curved boundaries.…

Numerical Analysis · Mathematics 2023-09-06 Nabil M. Atallah , Vladimir Z. Tomov , Guglielmo Scovazzi

A new framework is introduced for constructing interpretable and truly reliable reduced models for multiscale problems in situations without scale separation. Hydrodynamic approximation to the kinetic equation is used as an example to…

Computational Physics · Physics 2019-10-31 Jiequn Han , Chao Ma , Zheng Ma , Weinan E

We establish, for smooth enough initial data, the global well-posedness (existence, uniqueness and continuous dependence on initial data) of solutions, for an inviscid three-dimensional {\it slow limiting ocean dynamics} model. This model…

Analysis of PDEs · Mathematics 2013-11-26 Chongsheng Cao , Aseel Farhat , Edriss S. Titi

The scattering of electromagnetic waves from obstacles with wave-material interaction in thin layers on the surface is described by generalized impedance boundary conditions, which provide effective approximate models. In particular, this…

Numerical Analysis · Mathematics 2022-02-04 Jörg Nick , Balázs Kovács , Christian Lubich

Polydispersity is believed to have important effects on the formation of liquid crystal phases in suspensions of rod-like particles. To understand such effects, we analyse the phase behaviour of thin hard rods with length polydispersity.…

Soft Condensed Matter · Physics 2010-12-14 Alessandro Speranza , Peter Sollich
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