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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

In this work, the space of admissible entropy functions for the compressible multicomponent Euler equations is explored, following up on [Harten, \textit{J. Comput. Phys.}, 49 (1), 1983, pp. 151-164]. This effort allows us to prove a…

Analysis of PDEs · Mathematics 2019-09-24 Ayoub Gouasmi , Karthik Duraisamy , Scott M. Murman , Eitan Tadmor

A highly efficient three-dimensional (3D) Lattice Boltzmann (LB) model for high speed compressible flows is proposed. This model is developed from the original one by Kataoka and Tsutahara[Phys. Rev. E 69, 056702 (2004)]. The convection…

Statistical Mechanics · Physics 2010-12-14 Feng Chen , Aiguo Xu , Guangcai Zhang , Yingjun Li

In this work we analyze the entropic properties of the Euler equations when the system is closed with the assumption of a polytropic gas. In this case, the pressure solely depends upon the density of the fluid and the energy equation is not…

Numerical Analysis · Mathematics 2019-07-09 Andrew R. Winters , Christof Czernik , Moritz B. Schily , Gregor J. Gassner

The moment of entropy equation for vector-BGK model results in the entropy equation for macroscopic model. However, this is usually not the case in numerical methods because the current literature consists only of entropy conserving/stable…

Numerical Analysis · Mathematics 2023-10-31 Megala Anandan , S. V. Raghurama Rao

The problem of energy conservation in the lattice Boltzmann method is solved. A novel model with energy conservation is derived from Boltzmann's kinetic theory. It is demonstrated that the full thermo-hydrodynamics pertinent to the…

Statistical Mechanics · Physics 2007-05-23 S. Ansumali , I. V. Karlin

This study proposes a novel spatial discretization procedure for the compressible Euler equations which guarantees entropy conservation at a discrete level when an arbitrary equation of state is assumed. The proposed method, based on a…

Fluid Dynamics · Physics 2025-09-24 Alessandro Aiello , Carlo De Michele , Gennaro Coppola

We define the entropy S and uncertainty function of a squeezed system interacting with a thermal bath, and study how they change in time by following the evolution of the reduced density matrix in the influence functional formalism. As…

Quantum Physics · Physics 2014-11-18 D. Koks , A. Matacz , B. L. Hu

We demonstrate that in the space of distributions operated on by lattice Boltzmann methods that there exists a vicinity of the equilibrium where collisions with entropy balance are possible and, at the same time, there exist an area of…

Computational Physics · Physics 2013-08-05 A. N. Gorban , D. Packwood

Boltzmann defined the entropy of a macroscopic system in a macrostate $M$ as the $\log$ of the volume of phase space (number of microstates) corresponding to $M$. This agrees with the thermodynamic entropy of Clausius when $M$ specifies the…

Statistical Mechanics · Physics 2009-11-10 S. Goldstein , Joel L. Lebowitz

We consider two models of a compressible inviscid isentropic two-fluid flow. The first one describes the liquid-gas two-phase flow. The second one can describe the mixture of two fluids of different densities or the mixture of fluid and…

Analysis of PDEs · Mathematics 2019-05-01 Lizhi Ruan , Yuri Trakhinin

Atmospheric systems incorporating thermal dynamics must be stable with respect to both energy and entropy. While energy conservation can be enforced via the preservation of the skew-symmetric structure of the Hamiltonian form of the…

Numerical Analysis · Mathematics 2023-10-31 Kieran Ricardo , David Lee , Kenneth Duru

Experimental and theoretical results about entropy limits for macroscopic and single-particle systems are reviewed. It is clarified when it is possible to speak about a quantum of entropy, given by the Boltzmann constant k, and about a…

Quantum Physics · Physics 2023-11-06 Uwe Hohm , Christoph Schiller

This paper proposes a hierarchy of numerical fluxes for the compressible flow equations which are kinetic-energy and pressure equilibrium preserving and asymptotically entropy conservative, i.e., they are able to arbitrarily reduce the…

Fluid Dynamics · Physics 2024-08-08 Carlo De Michele , Gennaro Coppola

The focus of the present research is on the analysis of local energy stability of high-order (including split-form) summation-by-parts methods, with e.g. two-point entropy-conserving fluxes, approximating non-linear conservation laws. Our…

Numerical Analysis · Mathematics 2021-11-08 Gregor J. Gassner , Magnus Svärd , Florian J. Hindenlang

We study nonequilibrium thermodynamic properties of a driven one-dimensional quantum fluid by combining nonlinear Luttinger liquid theory with the quantum kinetic equation. In particular, we derive an entropy production consistent with the…

Mesoscale and Nanoscale Physics · Physics 2019-10-09 Edvin G. Idrisov , Thomas L. Schmidt

Moist thermodynamics is a fundamental driver of atmospheric dynamics across all scales, making accurate modeling of these processes essential for reliable weather forecasts and climate change projections. However, atmospheric models often…

Atmospheric and Oceanic Physics · Physics 2024-11-18 Kieran Ricardo , David Lee , Kenneth Duru

We present a series of three-dimensional discrete Boltzmann (DB) models for compressible flows in and out of equilibrium. The key formulating technique is the construction of discrete equilibrium distribution function through inversely…

Fluid Dynamics · Physics 2018-03-06 Yanbiao Gan , Aiguo Xu , Guangcai Zhang , Huilin Lai

In this paper, we derive entropy estimates for a class of schemes for the Euler equations which present the following features: they are based on the internal energy equation (eventually with a positive corrective term at the righ-hand-side…

Numerical Analysis · Mathematics 2017-07-06 Thierry Gallouet , Raphaele Herbin , J. -C Latché , N Therme

Many fundamental one-dimensional lattice models such as the Heisenberg or the Hubbard model are integrable. For these microscopic models, parameters in the Luttinger liquid theory can often be fixed and parameter-free results at low…

Strongly Correlated Electrons · Physics 2012-08-14 J. Sirker