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Development and Comparative Studies of Three Non-free Parameter lattice Boltzmann models for Simulation of Compressible Flows

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Advances in Applied mathematics and mechanics 2012年第4期4卷 454-472页

作者： l.m.yang C.Shu J.Wu Department of Aerodynamics College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsYudao StreetNanjing 210016JiangsuChina Department of mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260Singapore

This paper at first shows the details of finite volume-based lattice Boltzmann method(FV-lBm)for simulation of compressible flows with shock *** the FV-lBm,the normal convective flux at the interface of a cell is evaluated by using one-dimensional compressible lattice Boltzmann model,while the tangential flux is calculated using the same way as used in the conventional Euler *** paper then presents a platform to construct one-dimensional compressible lattice Boltzmann model for its use in *** platform is formed from the conservation forms of *** the platform,both the equilibrium distribution functions and lattice velocities can be determined,and therefore,non-free parameter model can be *** paper particularly presents three typical non-free parameter models,D1Q3,D1Q4 and *** performances of these three models for simulation of compressible flows are investigated by a brief analysis and their application to solve some one-dimensional and two-dimensional test *** results showed that D1Q3 model costs the least computation time and D1Q4 and D1Q5 models have the wider application range of mach *** the results,it seems that D1Q4 model could be the best choice for the FVlBm simulation of hypersonic flows.

关键词： FV-lBm non-free parameter models compressible inviscid flows

A Boundary Condition-Implemented Immersed Boundary-lattice Boltzmann method and Its Application for Simulation of Flows Around a Circular Cylinder

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Advances in Applied mathematics and mechanics 2014年第6期6卷 811-829页

作者： X.Wang C.Shu J.Wu l.m.yang Department of Aerodynamics College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsYudao StreetNanjing 210016China Department of mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260Singapore

A boundary condition-implemented immersed boundary-lattice Boltzmann method(IB-lBm)is presented in this *** present approach is an improvement to the conventional *** the conventional IB-lBm,the no-slip boundary condition is only approximately *** a result,there is flow penetration to the solid *** drawback of conventional IB-lBm is the use of Dirac delta function interpolation,which only has the first order of *** this work,the no-slip boundary condition is directly implemented,and used to correct the velocity at two adjacent mesh points from both sides of the boundary *** velocity correction is made through the second-order polynomial interpolation rather than the first-order delta function ***,the two drawbacks of conventional IB-lBm are removed in the present *** important contribution of this paper is to present a simple way to compute the hydrodynamic forces on the boundary from Newton’s second *** validate the proposed method,the two-dimensional vortex decaying problem and incompressible flow over a circular cylinder are *** shown in the present results,the flow penetration problem is eliminated,and the obtained results compare very well with available data in the literature.

关键词： Immersed boundary method lattice Boltzmann method velocity correction lagrange interpolation no-slip boundary condition

A Simplified lattice Boltzmann method without Evolution of Distribution Function

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Advances in Applied mathematics and mechanics 2017年第1期9卷 1-22页

作者： Z.Chen C.Shu Y.Wang l.m.yang D.Tan Department of mechanical Engineering National University of Singapore 10 Kent Ridge CrescentSingapore 119260 Department of Aerodynamics College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsYudao StreetNanjingJiangsu 210016China

In this paper,a simplified lattice Boltzmann method(SlBm)without evolution of the distribution function is developed for simulating incompressible viscous *** method is developed from the application of fractional step technique to the macroscopic Navier-Stokes(N-S)equations recovered from lattice Boltzmann equation by using Chapman-Enskog expansion *** SlBm,the equilibrium distribution function is calculated from the macroscopic variables,while the non-equilibrium distribution function is simply evaluated from the difference of two equilibrium distribution ***,SlBm tracks the evolution of the macroscopic variables rather than the distribution *** a result,lower virtual memories are required and physical boundary conditions could be directly *** numerical test at high Reynolds number,the method shows very nice performance in numerical *** accuracy test for the 2D Taylor-Green flow shows that SlBm has the second-order of accuracy in *** benchmark tests,including the Couette flow,the Poiseuille flow as well as the 2D lid-driven cavity flow,are conducted to further validate the present method;and the simulation results are in good agreement with available data in literatures.

关键词： Chapman-Enskog expansion analysis lattice Boltzmann equation Navier-Stokes equations memory cost stability

A three-dimensional gas-kinetic flux solver for simulation of viscous flows with explicit formulations of conservative variables and numerical flux

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Advances in Aerodynamics 2020年第1期2卷 250-277页

作者： Y.Sun l.m.yang C.Shu C.J.Teo Huawei Technologies Co. LtdBantianLonggang DistrictShenzhen 518129China Department of mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260Singapore

A truly three-dimensional(3D)gas-kinetic flux solver for simulation of incompressible and compressible viscous flows is presented in this *** local reconstruction of continuous Boltzmann equation,the inviscid and viscous fluxes across the cell interface are evaluated simultaneously in the *** from conventional gaskinetic scheme,in the present work,the distribution function at cell interface is computed in a straightforward *** an extension of our previous work(Sun et al.,Journal of Computational Physics,300(2015)492–519),the non-equilibrium distribution function is calculated by the difference of equilibrium distribution functions between the cell interface and its surrounding *** a result,the distribution function at cell interface can be simply calculated and the formulations for computing the conservative flow variables and fluxes can be given *** validate the proposed flux solver,several incompressible and compressible viscous flows are *** results show that the current scheme can provide accurate numerical results for three-dimensional incompressible and compressible viscous flows.

关键词： 3D flux solver Gas-kinetic scheme Viscous flow Navier-Stokes equations 1 Introduction

Adaptive partitioning-based discrete unified gas kinetic scheme for flows in all flow regimes

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Advances in Aerodynamics 2023年第1期5卷 282-311页

作者： l.m.yang l.C.Han H.Ding Z.H.li C.Shu Y.Y.liu Department of Aerodynamics College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China State Key laboratory of mechanics and Control of mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China Department of modern mechanics University of Science and Technology of ChinaHefei 230027China National laboratory for Computational Fluid Dynamics Beihang UniversityBeijing 100191China Department of mechanical Engineering National University of SingaporeSingapore 117576Singapore

To improve the efficiency of the discrete unified gas kinetic scheme(DUGKS)in capturing cross-scale flow physics,an adaptive partitioning-based discrete unified gas kinetic scheme(ADUGKS)is developed in this *** ADUGKS is designed from the discrete characteristic solution to the Boltzmann-BGK equation,which contains the initial distribution function and the local equilibrium *** initial distribution function contributes to the calculation of free streaming fluxes and the local equilibrium state contributes to the calculation of equilibrium *** the contribution of the initial distribution function is negative,the local flow field can be regarded as the continuous flow and the Navier-Stokes(N-S)equations can be used to obtain the solution ***,the discrete distribution functions should be updated by the Boltzmann equation to capture the rarefaction *** this,in the ADUGKS,the computational domain is divided into the DUGKS cell and the N-S cell based on the contribu-tion of the initial distribution function to the calculation of free streaming *** the N-S cell,the local flow field is evolved by solving the N-S equations,while in the DUGKS cell,both the discrete velocity Boltzmann equation and the correspond-ing macroscopic governing equations are solved by a modified *** more and more cells turn into the N-S cell with the decrease of the Knudsen number,a significant acceleration can be achieved for the ADUGKS in the continuum flow regime as compared with the DUGKS.

关键词： Boltzmann-BGK equation Discrete unified gas kinetic scheme Adaptive partitioning Discrete characteristic solution All flow regimes

On-line Preconcentration with Alkyl Phosphinic Acid Extraction Resin Coupled with ICP-mS/VG-AFS of Trace Rare Earth Elements and Cadmium in Seawater

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On-line Preconcentration with Alkyl Phosphinic Acid Extracti...

On calculating glacial isostatic adjustment

第三十五届国际光谱会议

作者： Q.Fu l.m.yang Q.Q.Wang~* Department of Chemistry & the mOE Key laboratory of modern Analytical Sciences College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China

＜正＞A novel alkyl phosphinic acid resin （APAR） has been synthesized via chlommethylation and phosphorylation reaction on styrene-divinylbenzene copolymer beads. The unit structure of the resin is shown in Fig.1. On-line preconcentration method for the determination of ultra trace rare earth elements (REEs,including

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Geodesy and Geodynamics 2024年第5期15卷 441-452页

作者： l.m.Cathles Cornell University IthacaNY 14853USA

modeling the earth's fluid and elastic response to the melting of the glaciers of the last ice age is the most direct way to infer the earth's radial viscosity ***,we compare two methods for calculating the viscoelastic response to surface *** one,the elastic equation of motion is converted to a viscoelastic equation using the Correspondence *** the other,elastic deformation is added to the viscous flow as isostatic adjustment *** two modeling methods predict adjustment histories that are different enough to potentially impact the interpretation of the observed glacial isostatic adjustment(GIA).The differences arise from buoyancy and whether fluid displacements are subjected to hydrostatic *** methods agree if they use the same equations and boundary *** origin of the differences is determined by varying the boundary conditions and pre-stress application.

关键词： Glacial isostatic adjustment Viscoelastic normal modes Hydrostatic pre-stress Elastic buoyancy Correspondence principle

Uncovering the hierarchical clusters in the heat-affected zone of an electron beam weldedα/βtitanium alloy joint

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Journal of materials Science & Technology 2024年第7期174卷 120-132页

作者： C.Xu X.H.Shao H.J.yang m.lv H.Q.liu X.l.ma Shenyang National laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Suzhou laboratory Suzhou 215028China Department of mechanical Engineering Kyushu UniversityFukuoka 819-0395Japan Bay Area Center for Electron microscopy Songshan Lake Materials LaboratoryDongguan 523808China

Using high-resolution transmission Kikuchi diffraction(TKD)and transmission electron microscopy(TEm),we examined the hierarchical clusters that form in situ in the heat-affected zone(HAZ),which are com-monly referred to as“ghost”structures,of bimodal titanium alloy Ti-5Al-2Sn-2Zr-4mo-4Cr(wt%,TC17).The ghost structures are enriched with Al elements but poor in mo and Cr compared to the surroundingβ*** results show that the ghost structure in middle-HAZ mainly consists ofα_(l)laths with a high-angle grain boundary,which exhibits the classic Burgers orientation relationship(BOR)with the host matrix,while it encircles theα_(P)grains in *** the ghost structure is evidenced to form via in-complete martensitic *** results further confirm that the ghost structure is composed ofαl and tinyβ_(l)laths with BOR,with the former being enriched with Al and poor with Cr and mo,while the latter is the ***,twoα_(l)variant clusters with a check-mark morphology are fre-quently observed viewed along[0001]_(αl)//[110]_(βl)directions,which are dominated by the crystallographic and geometrical relationships betweenαandβ*** on the microstructural characterization,it is hypothesized that the ghost structure is transformed from the initialα_(P)phase,due to the coupling ef-fect of high thermal stress(which induces the formation of a large number of dislocations)and element diffusion caused by sudden temperature increase and plunge cooling in the HAZ during the welding pro-cess.

关键词： TC17 titanium alloy Electron beam welding(EBW) The ghost structure Transmission Kikuchi diffraction(TKD) Transmission electron microscopy(TEm)

The Influence of Cysteine on the Bioavailability of Cadmium to Phaeodactylum Tricornutum

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The Influence of Cysteine on the Bioavailability of Cadmium ...