Extended BGK Boltzmann for Dense Gases

Suryanarayanan, Saikishan; Singh, Shiwani; Ansumali, Santosh

doi:10.4208/cicp.401011.220212s

Cited by 8 publications

(5 citation statements)

References 34 publications

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“…When ρ l and ρ g are given, the viscosity ratio υ g /υ l will be determined. Following the molecular theory, in the LB community Suryanarayanan et al [51] have adopted a variable viscosity ratio for simulating dense gases. In the present work, in order to investigate the effect of the viscosity ratio on the pseudopotential LB model, we employ various values of υ g /υ l for given ρ l and ρ g , and it is found that a lower liquid kinematic viscosity can be gained with the increase of υ g /υ l .…”

Section: Droplet Splashing On a Thin Liquid Filmmentioning

confidence: 99%

Lattice Boltzmann modeling of multiphase flows at large density ratio with an improved pseudopotential model

2013

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Owing to its conceptual simplicity and computational efficiency, the pseudopotential multiphase lattice Boltzmann (LB) model has attracted significant attention since its emergence. In this work, we aim to extend the pseudopotential LB model to simulate multiphase flows at large density ratio and relatively high Reynolds number. First, based on our recent work [Q. Li, K. H. Luo, and X. J. Li, Phys. Rev. E 86, 016709 (2012)], an improved forcing scheme is proposed for the multiple-relaxation-time pseudopotential LB model in order to achieve thermodynamic consistency and large density ratio in the model. Next, through investigating the effects of the parameter a in the Carnahan-Starling equation of state, we find that the interface thickness is approximately proportional to 1/ √ a. Using a smaller a will lead to a wider interface thickness, which can reduce the spurious currents and enhance the numerical stability of the pseudopotential model at large density ratio. Furthermore, it is found that a lower liquid viscosity can be gained in the pseudopotential model by increasing the kinematic viscosity ratio between the vapor and liquid phases. The improved pseudopotential LB model is numerically validated via the simulations of stationary droplet and droplet oscillation. Using the improved model as well as the above treatments, numerical simulations of droplet splashing on a thin liquid film are conducted at a density ratio in excess of 500 with Reynolds numbers ranging from 40 to 1000. The dynamics of droplet splashing is correctly reproduced and the predicted spread radius is found to obey the power law reported in the literature.

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Section: Droplet Splashing On a Thin Liquid Filmmentioning

confidence: 99%

Lattice Boltzmann modeling of multiphase flows at large density ratio with an improved pseudopotential model

2013

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“…The above model of free-energy is the simplest model that gives two stable phases provided F has two minima and was first formulated by van der Waals [72]. The macroscopic mass and momentum conservation equations are given by [74,75]…”

Section: Nonideal Fluids and Two-phase Flowmentioning

confidence: 99%

“…The above form of g nid α , known as the pressure formulation, is sufficient to incorporate the nonideal interactions and the Korteweg's stress tensor in the lattice Boltzmann model [40,69,74]. Alternatively, by exploiting the Gibbs-Duhem relation one can write the chemical potential formulation as [69,75]…”

Section: Nonideal Fluids and Two-phase Flowmentioning

confidence: 99%

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Lattice Boltzmann model for weakly compressible flows

et al. 2020

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We present an energy conserving lattice Boltzmann model based on a crystallographic lattice for simulation of weakly compressible flows. The theoretical requirements and the methodology to construct such a model are discussed. We demonstrate that the model recovers the isentropic sound speed in addition to the effects of viscous heating and heat flux dynamics. Several test cases for acoustics, thermal and thermoacoustic flows are simulated to show the accuracy of the proposed model. :1909.08406v1 [physics.comp-ph] arXiv

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“…Luo (1998), He et al (1998), Wang et al (2020), Su et al (2023) and Busuioc (2023). Based on the intuitive observations of the underlying molecular physics, various types of simple kinetic models (Suryanarayanan, Singh & Ansumali 2013;Takata & Noguchi 2018;Takata, Matsumoto & Hattori 2021) have been developed for the van der Waals fluids, which have been applied successfully to the study of phase transition problems. However, these models are either limited to the low-speed/isothermal flows or fail to reproduce the correct transport coefficients.…”

Section: Introductionmentioning

confidence: 99%

Molecular kinetic modelling of non-equilibrium transport of confined van der Waals fluids

Shan,

Su,

Gibelli

et al. 2023

J. Fluid Mech.

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A thermodynamically consistent kinetic model is proposed for the non-equilibrium transport of confined van der Waals fluids, where the long-range molecular attraction is considered by a mean-field term in the transport equation, and the transport coefficients are tuned to match the experimental data. The equation of state of the van der Waals fluids can be obtained from an appropriate choice of the pair correlation function. By contrast, the modified Enskog theory predicts non-physical negative transport coefficients near the critical temperature and may not be able to recover the Boltzmann equation in the dilute limit. In addition, the shear viscosity and thermal conductivity are predicted more accurately by taking gas molecular attraction into account, while the softened Enskog formula for hard-sphere molecules performs better in predicting the bulk viscosity. The present kinetic model agrees with the Boltzmann model in the dilute limit and with the Navier–Stokes equations in the continuum limit, indicating its capability in modelling dilute-to-dense and continuum-to-non-equilibrium flows. The new model is examined thoroughly and validated by comparing it with the molecular dynamics simulation results. In contrast to the previous studies, our simulation results reveal the importance of molecular attraction even for high temperatures, which holds the molecules to the bulk while the hard-sphere model significantly overestimates the density near the wall. Because the long-range molecular attraction is considered appropriately in the present model, the velocity slip and temperature jump at the surface for the more realistic van der Waals fluids can be predicted accurately.

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Extended BGK Boltzmann for Dense Gases

Cited by 8 publications

References 34 publications

Lattice Boltzmann modeling of multiphase flows at large density ratio with an improved pseudopotential model

Lattice Boltzmann modeling of multiphase flows at large density ratio with an improved pseudopotential model

Lattice Boltzmann model for weakly compressible flows

Molecular kinetic modelling of non-equilibrium transport of confined van der Waals fluids

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