Lattice Boltzmann simulations of nonequilibrium fluctuations in a nonideal binary mixture.

Phys Rev E

Laboratoire de Physique de Ecole Normale Superieure de Lyon (CNRS UMR5672), 46 Allée d'Italie, 69364, Lyon, France.

Published: June 2019

In recent years the lattice Boltzmann (LB) methodology has been fruitfully extended to include the effects of thermal fluctuations. So far, all studied cases pertain to equilibrium fluctuations, i.e., fluctuations with respect to an equilibrium background state. In this paper we take a step further and present results of fluctuating LB simulations of a binary mixture confined between two parallel walls in the presence of a constant concentration gradient in the wall-to-wall direction. This is a paradigmatic setup for the study of nonequilibrium (NE) fluctuations, i.e., fluctuations with respect to a nonequilibrium state. We analyze the dependence of the structure factors for the hydrodynamical fields on the wave vector q in both the directions parallel and perpendicular to the walls, highlighting the long-range (∼|q|^{-4}) nature of correlations in the NE framework. Results at the small scales (high wave numbers) quantitatively agree with the predictions of fluctuating hydrodynamics without fitting parameters. At larger scales (low wave numbers), however, results show finite-size effects induced by confinement and call for further studies aimed at controlling boundary conditions in the fluctuating LB framework as well as compressibility effects. Moreover, in the presence of a nonideal equation of state of the mixture, we also observe that the (spatially homogeneous) average pressure changes, due to a genuinely new contribution triggered by NE fluctuations. These NE pressure effects are studied at changing the system size and the concentration gradient. Taken all together, we argue that the results of this article are useful and instrumental to boost the applicability of the fluctuating LB methodology in the framework of NE fluctuations, possibly in conjunction with experiments.

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevE.99.063302DOI Listing

Publication Analysis

Top Keywords

lattice boltzmann
8
fluctuations
8
nonequilibrium fluctuations
8
binary mixture
8
fluctuations fluctuations
8
fluctuations respect
8
concentration gradient
8
wave numbers
8
boltzmann simulations
4
simulations nonequilibrium
4

Similar Publications

Lattice Boltzmann Modeling of Additive Manufacturing of Functionally Graded Materials.

Entropy (Basel)

December 2024

AGH University of Krakow, Faculty of Metals Engineering and Industrial Computer Science, al. Mickiewicza 30, 30-059 Kraków, Poland.

Functionally graded materials (FGMs) show continuous variations in properties and offer unique multifunctional capabilities. This study presents a simulation of the powder bed fusion (PBF) process for FGM fabrication using a combination of Unity-based deposition and lattice Boltzmann method (LBM)-based process models. The study introduces a diffusion model that allows for the simulation of material mixtures, in particular AISI 316L austenitic steel and 18Ni maraging 300 martensitic steel.

View Article and Find Full Text PDF

Lattice thermal conductivity in CrSBr: the effects of interlayer interaction, magnetic ordering and external strain.

J Phys Condens Matter

January 2025

South China Normal University, School of Physics, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangzhou, 510631, CHINA.

With the continuous development of digital information and big data technologies, the ambient temperature and heat generation during the operation of magnetic storage devices play an increasingly crucial role in ensuring data security and device stability. In this study, we examined the lattice thermal conductivity of the van der Waals magnetic semiconductor CrSBr from bulk to monolayer structures using first-principles calculations and the phonon Boltzmann transport equation. Our results indicated that lattice thermal conductivity show anisotropy and CrSBr bilayer exhibits lower thermal conductivity at all temperatures.

View Article and Find Full Text PDF

Background: Left ventricular assist device (LVAD) has been widely used as an alternative treatment for heart failure, however, aortic regurgitation is a common complication in patients with LVAD support. And the O-A angle (the angle between LVAD outflow graft and the aorta) is considered as a vital factor associated with the function of aortic valve. To date, the biomechanical effect of the O-A angle on the aortic valve remains largely unknown.

View Article and Find Full Text PDF

Phonon thermal transport in BiTe/SbTe monolayer superlattices: a neural network potential study.

Nanoscale

January 2025

Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China.

Superlattices are significant means to reduce the lattice thermal conductivity of thermoelectric materials and optimize their performance. In this work, using high-precision first-principles based neural network potentials combined with non-equilibrium molecular dynamics simulations and the phonon Boltzmann transport equation, the lattice thermal conductivities of BiTe monolayer and lateral BiTe/SbTe monolayer superlattices are thoroughly investigated. As the period length increases, the thermal conductivity shows a trend of an initial decrease followed by an increase, which aligns with conventional observations.

View Article and Find Full Text PDF

Investigating Cell-Induced Mixing Dynamics in Microfluidic Droplets Using the Lattice Boltzmann Method.

Langmuir

January 2025

CNNFM Lab, School of Mechanical Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563 Tehran, Iran.

This study investigates the impact of cell dynamics on mixing efficiency within a microfluidic droplet, emphasizing the relationship between cell motion, deformability, and resultant asymmetry in velocity and concentration fields. Simulations were conducted for droplets containing encapsulated cells at varying Peclet numbers ( = 100-800) and coupling constants ( = 0.0025, 0.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!