1,721,290 research outputs found
Matrix lattice Boltzmann reloaded
Full text linkThe lattice Boltzmann equation has been introduced about twenty years ago as a new paradigm for computational fluid dynamics. In this paper, we revisit the main formulation of the lattice Boltzmann collision integral (matrix model) and introduce a new two-parametric family of collision operators which permits to combine enhanced stability and accuracy of matrix models with the outstanding simplicity of the most popular single-relaxation time schemes. The option of the revised lattice Boltzmann equation is demonstrated through numerical simulations of a three-dimensional lid driven cavity
Integral form of the Boltzmann equation for the forced diffusion of charged particles in anisotropically scattering media
No full textNumerical validation of the quantum lattice Boltzmann scheme in two and three dimensions
No full textDeterminazione numerica della resistenza al moto di una corrente attraverso tenute statiche a labirinto
No full textAnalytical calculation of slip flow in lattice boltzmann models with kinetic boundary conditions
No full textWe discuss the emergence of boundary slip in mesoscopic lattice Boltzmann models for microflows
Towards a mean-field kinetic model of electroweak baryogenesis
No full textWe explore the dynamic symmetry breaking between the mass of two annihilating species entrapped within a condensing droplet of a third phase-changing species. The symmetry breaking is induced by different diffusivities and/or diffebet source terms acting at the droplet interface. Potential implications for the problem of electroweak baryogenesis are sketched out
On the effects of reactant flow rarefaction on heterogeneous catalysis: A regularized lattice Boltzmann study
No full textIn this paper, a numerical investigation on heterogeneous catalysis is performed by means of a Regularized Lattice BGK approach. The effects of different values of the reactant flow Knudsen numbers are evaluated, in terms of conversion efficiency and penetration inside the structure of a nano-porous gold ingot. The results are in line with experimental evidence in the literature and open interesting perspectives for the optimal design of future nano-catalytic devices
Dynamic symmetry-breaking in mutually annihilating fluids with selective interfaces
No full textThe selective entrapment of mutually annihilating species within a phase-changing carrier fluid is explored by both analytical and numerical means. The model takes full account of the dynamic heterogeneity which arises as a result of the coupling between hydrodynamic transport, dynamic phase-transitions and chemical reactions between the participating species, in the presence of a selective droplet interface. Special attention is paid to the dynamic symmetry breaking between the mass of the two species entrapped within the expanding droplet as a function of time. It is found that selective sources are much more effective symmetry breakers than selective diffusion. The present study may be of interest for a broad variety of advection-diffusion-reaction phenomena with selective fluid interfaces, including the problem of electroweak baryogenesis
Ground-state computation of Bose-Einstein condensates by an imaginary-time quantum lattice Boltzmann scheme
No full textThe multidimensional formulation of the quantum lattice Boltzmann (qLB) scheme is extended to the case of nonlinear quantum wave equations. More specifically, imaginary-time formulations of the qLB scheme are developed and applied to the numerical computation of the ground state of the Gross-Pitaevskii equation in one and two spatial dimensions. The calculation is validated through detailed comparison with other numerical methods, as well as with analytical results based on the Thomas-Fermi approximation. The linear scaling of the time-step size with the spatial mesh spacing, a distinctive feature of the present quantum kinetic approach, is also numerically demonstrated
Colloquium: Role of the H theorem in lattice Boltzmann hydrodynamic simulations
No full textIn the last decade, minimal kinetic models, and primarily the lattice Boltzmann equation, have met with significant success in the simulation of complex hydrodynamic phenomena, ranging from slow flows in grossly irregular geometries to fully developed turbulence, to flows with dynamic phase transitions. Besides their practical value as efficient computational tools for the dynamics of complex systems, these minimal models may also represent a new conceptual paradigm in modern computational statistical mechanics: instead of proceeding bottom-up from the underlying microdynamic systems, these minimal kinetic models are built top-down starting from the macroscopic target equations. This procedure can provide dramatic advantages, provided the essential physics is not lost along the way. For dissipative systems, one essential requirement is compliance with the second law of thermodynamics. In this Colloquium, the authors present a chronological survey of the main ideas behind the lattice Boltzmann method, with special focus on the role played by the H theorem in enforcing compliance of the method with macroscopic evolutionary constraints (the second law) as well as in serving as a numerically stable computational tool for fluid flows and other dissipative systems out of equilibrium
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