搜索到742篇“ PSEUDOPOTENTIAL“的相关文章
Numerical Stability and Accuracy of Contact Angle Schemes in Pseudopotential Lattice Boltzmann Model for Simulating Static Wetting and Dynamic Wetting
2023年
There are five most widely used contact angle schemes in the pseudopotential lattice Boltzmann(LB)model for simulating the wetting phenomenon:The pseudopotential-based scheme(PB scheme),the improved virtualdensity scheme(IVD scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the fluid layer density above the wall(MPB-C scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the weighted average density of surrounding fluid nodes(MPB-W scheme)and the geometric formulation scheme(GF scheme).But the numerical stability and accuracy of the schemes for wetting simulation remain unclear in the past.In this paper,the numerical stability and accuracy of these schemes are clarified for the first time,by applying the five widely used contact angle schemes to simulate a two-dimensional(2D)sessile droplet on wall and capillary imbibition in a 2D channel as the examples of static wetting and dynamic wetting simulations respectively.(i)It is shown that the simulated contact angles by the GF scheme are consistent at different density ratios for the same prescribed contact angle,but the simulated contact angles by the PB scheme,IVD scheme,MPB-C scheme and MPB-W scheme change with density ratios for the same fluid-solid interaction strength.The PB scheme is found to be the most unstable scheme for simulating static wetting at increased density ratios.(ii)Although the spurious velocity increases with the increased liquid/vapor density ratio for all the contact angle schemes,the magnitude of the spurious velocity in the PB scheme,IVD scheme and GF scheme are smaller than that in the MPB-C scheme and MPB-W scheme.(iii)The fluid density variation near the wall in the PB scheme is the most significant,and the variation can be diminished in the IVD scheme,MPB-C scheme andMPBWscheme.The variation totally disappeared in the GF scheme.(iv)For the simulation of capillary imbibition,the MPB-C scheme,MPB-Wscheme and GF scheme simulate the dynamics of the liq
Dongmin WangGaoshuai Lin
Pseudopotential-based discrete unified gas kinetic scheme for modeling multiphase fluid flows
2022年
To directly incorporate the intermolecular interaction effects into the discrete unified gas-kinetic scheme(DUGKS)for simulations of multiphase fluid flow,we developed a pseudopotential-based DUGKS by coupling the pseudopotential model that mimics the intermolecular interaction into DUGKS.Due to the flux reconstruction procedure,additional terms that break the isotropic requirements of the pseudopotential model will be introduced.To eliminate the influences of nonisotropic terms,the expression of equilibrium distribution functions is reformulated in a moment-based form.With the isotropy-preserving parameter appropriately tuned,the nonisotropic effects can be properly canceled out.The fundamental capabilities are validated by the flat interface test and the quiescent droplet test.It has been proved that the proposed pseudopotential-based DUGKS managed to produce and maintain isotropic interfaces.The isotropy-preserving property of pseudopotential-based DUGKS in transient conditions is further confirmed by the spinodal decomposition.Stability superiority of the pseudopotential-based DUGKS over the lattice Boltzmann method is also demonstrated by predicting the coexistence densities complying with the van der Waals equation of state.By directly incorporating the intermolecular interactions,the pseudopotential-based DUGKS offers a mesoscopic perspective of understanding multiphase behaviors,which could help gain fresh insights into multiphase fluid flow.
Zeren YangSha LiuCongshan ZhuoChengwen Zhong
A Pseudopotential Lattice Boltzmann Analysis for Multicomponent Flow
2022年
This paper presents a pseudopotential lattice Boltzmann analysis to show the deficiency of previous pseudopotential models,i.e.,inconsistency between equilibrium velocity and mixture velocity.To rectify this problem,there are two strategies:decoupling relaxation time and kinematic viscosity or introducing a system mixture relaxation time.Then,we constructed two modified models:a two-relaxationtime(TRT)scheme and a triple-relaxation-time(TriRT)scheme to decouple the relaxation time and kinematic viscosity.Meanwhile,inspired by the idea of a system mixture relaxation time,we developed three mixture models under different collision schemes,viz.mix-SRT,mix-TRT,and mix-TriRT models.Afterwards,we derived the advection-diffusion equation for the multicomponent system and derived the mutual diffusivity in a binarymixture.Finally,we conducted several numerical simulations to validate the analysis on these models.The numerical results show that these models can obtain smaller spurious currents than previous models and have a wider range for the accessible viscosity ratio with fourth-order isotropy.Compared to previous models,presentmodels avoid complex matrix operations and only fourth-order isotropy is required.The increased simplicity and higher computational efficiency of these models make them easy to apply to engineering and industrial applications.
Yong ZhaoGerald G.PereiraShibo KuangZhenhua ChaiBaochang Shi
A Quantitative Comparison of Physical Accuracy and Numerical Stability of Lattice Boltzmann Color Gradient and Pseudopotential Multicomponent Models for Microfluidic Applications
2022年
The performances of the Color-Gradient(CG)and the Shan-Chen(SC)multicomponent Lattice Boltzmann models are quantitatively compared side-by-side on multiple physical flow problems where breakup,coalescence and contraction of fluid ligaments are important.The flow problems are relevant to microfluidic applications,jetting of microdroplets as seen in inkjet printing,as well as emulsion dynamics.A significantly wider range of parameters is shown to be accessible for CG in terms of density-ratio,viscosity-ratio and surface tension values.Numerical stability for a high density ratio O(1000)is required for simulating the drop formation process during inkjet printing which we show here to be achievable using the CG model but not using the SC model.Our results show that the CG model is a suitable choice for challenging simulations of droplet formation,due to a combination of both numerical stability and physical accuracy.We also present a novel approach to incorporate repulsion forces between interfaces for CG,with possible applications to the study of stabilized emulsions.Specifically,we show that the CG model can produce similar results to a known multirange potentials extension of the SC model for modelling a disjoining pressure,opening up its use for the study of dense stabilized emulsions.
Karun P.N.DatadienGianluca Di StasoHerman M.A.WijshoffFederico Toschi
Investigation of cavitation bubble collapse in hydrophobic concave using the pseudopotential multi-relaxation-time lattice Boltzmann method被引量:1
2021年
The interaction between cavitation bubble and solid surface is a fundamental topic which is deeply concerned for the utilization or avoidance of cavitation effect.The complexity of this topic is that the cavitation bubble collapse includes many extreme physical phenomena and variability of different solid surface properties.In the present work,the cavitation bubble collapse in hydrophobic concave is studied using the pseudopotential multi-relaxation-time lattice Boltzmann model(MRT-LB).The model is modified by involving the piecewise linear equation of state and improved forcing scheme.The fluid-solid interaction in the model is employed to adjust the wettability of solid surface.Moreover,the validity of the model is verified by comparison with experimental results and grid-independence verification.Finally,the cavitation bubble collapse in a hydrophobic concave is studied by investigating density field,pressure field,collapse time,and jet velocity.The superimposed effect of the surface hydrophobicity and concave geometry is analyzed and explained in the framework of the pseudopotential LBM.The study shows that the hydrophobic concave can enhance cavitation effect by decreasing cavitation threshold,accelerating collapse and increasing jet velocity.
Minglei ShanYu YangXuemeng ZhaoQingbang HanCheng Yao
Spin–spin interactions in defects in solids from mixed all-electron and pseudopotential first-principles calculations
2021年
Understanding the quantum dynamics of spin defects and their coherence properties requires an accurate modeling of spinspin interaction in solids and molecules,for example by using spin Hamiltonians with parameters obtained from first principles calculations.We present a real-space approach based on density functional theory for the calculation of spin-Hamiltonian parameters,where only selected atoms are treated at the all-electron level,while the rest of the system is described with the pseudopotential approximation.Our approach permits calculations for systems containing more than 1000 atoms,as demonstrated for defects in diamond and silicon carbide.We show that only a small number of atoms surrounding the defect needs to be treated at the all-electron level,in order to obtain an overall all-electron accuracy for hyperfine and zero-field splitting tensors.We also present results for coherence times,computed with the cluster correlation expansion method,highlighting the importance of accurate spin-Hamiltonian parameters for quantitative predictions of spin dynamics.
Krishnendu GhoshHe MaMykyta OnizhukVikram GaviniGiulia Galli
关键词:SOLIDSHAMILTONIAN
一维吸引相互作用下p波费米气体的赝势研究
2021年
通过对零程相互作用下一维p波费米气体中两粒子间接触条件的分析,建立了忽略有效力程的相互作用边界条件与两粒子接触条件在表达上的等价性。在此基础上将有效力程这一相互作用参数引入模型中,通过引入δ′函数求得赝势的方法,给出了两种相互作用下的一维p波费米气体的赝势形式和一种新的粒子间接触条件。
郝舣航王美山
关键词:赝势
基于LBM伪势模型下的三维大密度液滴撞击壁面数值研究被引量:2
2020年
伪势多相MRT-LBM(多重松弛时间格子玻尔兹曼方法)模型由于理论简单,自动形成两相界面等特点,被大量应用于多相流中的液滴撞击以及气液相变等数值模拟问题。该文基于二维和三维大密度伪势MRT-LBM模型,研究了三维条件下的单液滴和连续双液滴撞击壁面过程。结果表明:三维MRT-LBM能很好地实现对单液低撞击过程的模拟,且能精确地捕捉不同润湿特性下的撞击过程。该模型在液滴碰撞的模拟中与实验结果吻合程度较高,较高的液滴雷诺数与亲水程度有利于液滴在壁面上的铺展。
李培生李志豪黄逸宸赵万东陈岳徐猛
关键词:多相流
全原子经验赝势法模拟InAs/InAsSbⅡ类超晶格被引量:1
2018年
为了研究InAs/InAs1-xSbxⅡ类超晶格结构的物理特性,首次采用全原子的经验赝势方法对InAs/InAs1-xSbx结构进行模拟,并对体系的近带边能级、单粒子波函数和带边跃迁矩阵元进行了计算。结果表明,量子限制效应造成超晶格带隙的宽化;超晶格中基态电子主要局域在InAs层,基态空穴主要局域在合金层,与相关体材料及I型超晶格所做的对比结果表明,电子、空穴的物理分离效应是造成体系载流子寿命较长的重要原因;将带边跃迁矩阵元作为衡量载流子寿命的重要元素,针对固定波段的超晶格系统进行优化,最终得到带边跃迁矩阵元更小的体系(163?) InAs/(82?) InAs0. 72Sb0. 28结构,其跃迁矩阵元是0. 010 684 3 a.u.。
马玲丽詹锋
关键词:跃迁矩阵元
液态法制备复合材料的多组分伪势LBM模拟被引量:1
2018年
采用修正的多组分伪势模型(EFM)模拟了液态法制备金属基复合材料过程中多孔介质内的浸渗过程,研究了黏度比(M)、壁面润湿性、雷诺数(Re)、孔隙率以及不同分形结构对浸渗过程的影响.结果表明:黏度比越大,浸渗饱和度(S)越低、浸渗时间(t)越短,并且M>90时,黏度比对饱和度和浸渗时间影响可忽略不计,此时接触角的影响较小; Re越小,浸渗饱和度越高、浸渗时间越长,同时壁面润湿性的影响越大;当入口Re一定时,孔隙率越小,分形多孔的渗透率越低,由于孔隙分布不均,造成流体在局部优先浸渗,导致浸渗时间减少、饱和度降低;对不同的分形多孔介质,壁面润湿性的影响有着明显的差异,对A类(标准分形)和C类(固体骨架偏右)的多孔介质,接触角(θ)越大,饱和度越低、浸渗时间越短;对B(固体骨架偏上)和D类(固体骨架偏左上)分形多孔,随接触角的增大,饱和度和浸渗时间均呈现先增加后减小的趋势,并且在接触角小于90°的区间内出现极值.
李培生王昭太赵万东钟源张莹
关键词:金属基复合材料多孔介质

相关作者

夏琼琼
作品数:2被引量:0H指数:0
供职机构:安徽师范大学物理与电子信息学院物理系
研究主题:DENSITY_FUNCTIONAL_THEORY IVE H2O DIMER BONDING
肖伟
作品数:6被引量:1H指数:1
供职机构:安徽师范大学
研究主题:GD DENSITY_FUNCTIONAL_THEORY 钆 结构和热力学性质 密度泛函理论
崔执凤
作品数:251被引量:629H指数:14
供职机构:安徽师范大学
研究主题:激光诱导击穿光谱 CIDEP 自由基 电子密度 激光诱导
宁利新
作品数:23被引量:22H指数:3
供职机构:安徽师范大学
研究主题:格位 CE3 EU 第一性原理研究 掺杂
章永凡
作品数:141被引量:270H指数:9
供职机构:福州大学
研究主题:电子结构 密度泛函理论 密度泛函研究 密度泛函 量子化学