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We derive equations for fluid dynamics from a non-extensive Boltzmann transport equation consistent with Tsallis' non-extensive entropy formula. We evaluate transport coefficients employing the relaxation time approximation and investigate…

Nuclear Theory · Physics 2015-05-30 T. S. Biro , E. Molnar

We derive an analytical theory of the PDF of density fluctuations in supersonic turbulence in the presence of gravity in star-forming clouds. The theory is based on a rigorous derivation of a combination of the Navier-Stokes continuity…

Astrophysics of Galaxies · Physics 2020-11-11 Etienne Jaupart , Gilles Chabrier

Motivated by various recent experimental findings, we propose a dynamical model of intermittently self-propelled particles: active particles that recurrently switch between two modes of motion, namely an active run-state and a turn state,…

Soft Condensed Matter · Physics 2025-10-30 Agniva Datta , Carsten Beta , Robert Großmann

An improved diffuse boundary condition, where the number flux of the incoming real molecules on the wall surface is calculated using the molecular variables rather than the cell's macroscopic variables, is proposed to eliminate the…

Computational Physics · Physics 2014-03-18 Jun Li

We study the spectral problem associated with the equation governing the small transverse motions of a viscoelastic tube of finite length conveying an ideal fluid. The boundary conditions considered are of general form, accounting for a…

Analysis of PDEs · Mathematics 2024-03-01 Xiao Xuan Feng , Mahyar Mahinzaeim , Gen Qi Xu

Employing molecular dynamics simulations of jammed soft particles, we study microscopic responses of force-chain networks to quasi-static isotropic (de)compressions. We show that not only contacts but also interparticle gaps between the…

Soft Condensed Matter · Physics 2026-03-26 Kuniyasu Saitoh , Vanessa Magnanimo , Stefan Luding

In conventional fluid mechanics, the chemical composition and thermodynamic state of a fluid-solid interface are not considered when establishing velocity-field boundary conditions. As a consequence, fluid simulations are usually not able…

Motivated by the result of invariance of regular-boundary open sets in \cite{CannarsaDaPratoFrankowska2009} and multi-stability issues in gene networks, our paper focuses on three closely related aims. First, we give a necessary local…

Optimization and Control · Mathematics 2018-08-14 Dan Goreac

The derivation of a Moving Boundary Approximation or of the response of a coherent structure like a front, vortex or pulse to external forces and noise, is generally valid under two conditions: the existence of a separation of time scales…

Condensed Matter · Physics 2009-10-31 Ute Ebert , Wim van Saarloos

Considering the example of interacting Brownian particles we present a linear response derivation of the boundary condition for the corresponding hydrodynamic description (the diffusion equation). This requires us to identify a non-analytic…

Statistical Mechanics · Physics 2009-11-07 M. Fuchs , K. Kroy

The existence and search for thermodynamic phase transitions is of unfading interest. In this paper, we present numerical evidence of dynamical phase transitions occurring in boundary driven systems with a constrained integrated current. It…

Statistical Mechanics · Physics 2017-03-29 Ohad Shpielberg , Yaroslav Don , Eric Akkermans

The lubrication theory is mostly concerned with the behavior of a lubricant flowing through a narrow gap. Motivated by the experimental findings from the tribology literature, we take the lubricant to be micropolar fluid and study its…

Analysis of PDEs · Mathematics 2025-07-16 Matthieu Bonnivard , Igor Pazanin , Francisco Suarez-Grau

We show that some boundary conditions assumed at a thin membrane may result in normal diffusion not being the stochastic Markov process. We consider boundary conditions defined in terms of the Laplace transform in which there is a linear…

Statistical Mechanics · Physics 2020-08-26 Tadeusz Kosztołowicz

We study closed systems of particles that are subject to stochastic forces in addition to the conservative forces. The stochastic equations of motion are set up in such a way that the energy is strictly conserved at all times. To ensure…

Statistical Mechanics · Physics 2022-10-05 Tânia Tomé , Mário J. de Oliveira

Additive noise in Partial Differential equations, in particular those of fluid mechanics, has relatively natural motivations. The aim of this work is showing that suitable multiscale arguments lead rigorously, from a model of fluid with…

Probability · Mathematics 2022-05-12 Franco Flandoli , Umberto Pappalettera

We study the existence of densities for distributions of piecewise deterministic Markov processes. We also obtain relationships between invariant densities of the continuous time process and that of the process observed at jump times. In…

Probability · Mathematics 2020-06-03 Piotr Gwiżdż , Marta Tyran-Kamińska

We consider the statistics for the vorticity field in two-dimensional homogeneous isotropic turbulence (HIT). First, we exploit the invariance properties to derive dimensionally reduced governing equations for the one-point and two-point…

Fluid Dynamics · Physics 2026-04-20 Qian Huang , Simon Görtz , Paul Hollmann , Johannes Conrad , Christian Rohde , Martin Oberlack

We study the fundamental problem of two gas species in two dimensional velocity space whose molecules collide as hard circles in the presence of a flat boundary and with dependence on only one space dimension. The case of three-dimensional…

Analysis of PDEs · Mathematics 2009-11-11 A. Sotirov

We consider the numerical integration of Langevin equations for particles in a channel, in the presence of boundary conditions fixing the concentration values at the ends. This kind of boundary condition appears for instance when…

Computational Physics · Physics 2020-07-24 Laureano Ramírez-Piscina

Position probability distribution of a set of massive mutually exclusive particles in one dimension has been defined. Examples with a given two mutually exclusive particles system are considered. It is emphasized that quantum particles at…

Quantum Physics · Physics 2016-10-28 Rasool Kheiry , Shahram Salehi