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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

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

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

Spalling characteristics of high-temperature treated granitic rock at different strain rates

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Journal of Rock mechanics and Geotechnical Engineering 2024年第4期16卷 1280-1288页

作者： l.F.Fan Q.H.yang X.l.Du The Key laboratory of Urban Security and Disaster Engineering of ministry of Education Beijing University of TechnologyBeijing100124China

The dynamic spalling characteristics of rock are important for stability analysis in rock *** paper presented an experimental investigation on the dynamic spalling characteristics of granite with different temperatures and strain rates.A series of dynamic spalling tests with different impact velocities were conducted on thermally treated granite at different *** dynamic spalling strengths of granite with different temperatures and strain rates were determined.A model was proposed to correlate the dynamic spalling strength of granite,high temperature and strain *** results show that the spalling strength of granite decreases with increasing ***,the spalling strength of granite with a higher strain rate is larger than that with a lower strain *** proposed model can describe the relationship among dynamic spalling strength of granite,high temperature and strain rate.

关键词： Dynamic spalling characteristics High temperature Strain rate Dynamic loading Granite

TGAIN: Geospatial Data Recovery Algorithm Based on GAIN-lSTm

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Computers, materials and Continua 2024年第1期81卷 1471-1489页

作者： yang l. li l. ma S. School of Soft Engineering Jinling Institute of Technology Nanjing 211169 China School of Computer Jinling Institute of Technology Nanjing 211169 China School of Network Security Jinling Institute of Technology Nanjing 211169 China

Accurate geospatial data are essential for geographic information systems (GIS), environmental monitoring, and urban planning. The deep integration of the open Internet and geographic information technology has led to increasing challenges in the integrity and security of spatial data. In this paper, we consider abnormal spatial data as missing data and focus on abnormal spatial data recovery. Existing geospatial data recovery methods require complete datasets for training, resulting in time-consuming data recovery and lack of generalization. To address these issues, we propose a GAIN-lSTm-based geospatial data recovery method (TGAIN), which consists of two main works: (1) it uses a long-short-term recurrent neural network (lSTm) as a generator to analyze geospatial temporal data and capture its temporal correlation; (2) it constructs a complete TGAIN network using a cue-masked fusion matrix mechanism to obtain data that matches the original distribution of the input data. The experimental results on two publicly accessible datasets demonstrate that our proposed TGAIN approach surpasses four contemporary and traditional models in terms of mean absolute error (mAE), root mean square error (RmSE), mean square error (mSE), mean absolute percentage error (mAPE), coefficient of determination (R2) and average computational time across various data missing rates. Concurrently, TGAIN exhibits superior accuracy and robustness in data recovery compared to existing models, especially when dealing with a high rate of missing data. Our model is of great significance in improving the integrity of geospatial data and provides data support for practical applications such as urban traffic optimization prediction and personal mobility analysis. © 2024 The Authors. Published by Tech Science Press.

关键词： data recovery generative adversarial networks Geospatial data temporal correlation

Application of Gaussian Beam Summation migration in Reflected In-seam Wave Imaging

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 276-284页

作者： HAN Jianguang lÜQingtian ZHANG Zhiheng yang Shun WANG Shuo Chinese Academy of Geological Sciences Beijing 100037China Shandong Taishan Resources Exploration Co. Ltd.Jinan 250104China

The geological conditions for coal mining in China are complex,with various structural issues such as faults and collapsed columns seriously compromising the safety of coal mine ***-seam wave exploration is an effective technique for acquiring detailed information on geological structures in coal seam working ***,the existing reflected in-seam wave imaging technique can no longer meet the exploration precision requirements,making it imperative to develop a new reflected in-seam wave imaging *** study applies the Gaussian beam summation(GBS)migration method to imaging coal seams'reflected in-seam wave ***,with regard to the characteristics of the reflected in-seam wave data,methods such as wavefield removal and enveloped superposition are employed for the corresponding wavefield separation,wave train compression and other processing of reflected in-seam ***,imaging is performed using the GBS migration *** feasibility and effectiveness of the proposed method for reflected in-seam wave imaging are validated by conducting GBS migration tests on 3D coal-seam fault models with different dip angles and *** applying the method to reflected in-seam wave data for an actual coal seam working face,accurate imaging of a fault structure is obtained,thereby validating its practicality.

关键词： reflected in-seam wave Gaussian beam summation migration numerical tests fault

Identification of candidate genes for early-maturity traits by combining BSA-seq and QTl mapping in upland cotton(Gossypium hirsutum l.)

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Journal of Integrative Agriculture 2024年第10期23卷 3472-3486页

作者： liang ma Tingli Hu meng Kang Xiaokang Fu Pengyun Chen Fei Wei Hongliang Jian Xiaoyan lü meng Zhang Yonglin yang State Key laboratory of Cotton Bio-breeding and Integrated Utilization/Institute of Cotton Research Chinese Academy ofAgricultural SciencesAnyang 455000China School of Agriculture Henan Institute of Science and TechnologyXinxiang 453003China Shihezi Academy of Agricultural Sciences Shihezi 832099China

Cotton breeding for the development of early-maturing varieties is an effective way to improve multiple cropping indexes and alleviate the conflict between grains and cotton in the cultivated fields in *** the present study,we aimed to identify upland cotton quantitative trait loci(QTls)and candidate genes related to early-maturity traits,including whole growth period(WGP),flowering timing(FT),node of the first fruiting branch(NFFB),height of the node of the first fruiting branch(HNFFB),and plant height(PH).An early-maturing variety,CCRI50,and a latematuring variety,Guoxinmian 11,were crossed to obtain biparental *** populations were used to map QTls for the early-maturity traits for two years(2020 and 2021).With BSA-seq analysis based on the data of population 2020,the candidate regions related to early maturity were found to be located on chromosome *** then developed 22 polymorphic insertions or deletions(InDel)markers to further narrow down the candidate regions,resulting in the detection of five and four QTls in the 2020 and 2021 populations,*** to the results of QTl mapping,two candidate regions(InDel_G286-InDel_G144 and InDel_G24-InDel_G43)were *** these regions,three genes(GH_D03G0451,GH_D03G0649,and GH_D03G1180)have nonsynonymous mutations in their exons and one gene(GH_D03G0450)has SNP variations in the upstream sequence between CCRI50 and Guoxinmian *** four genes also showed dominant expression in the floral *** expression levels of GH_D03G0451,GH_D03G0649 and GH_D03G1180 were significantly higher in CCRI50 than in Guoxinmian 11 during the bud differentiation stages,while GH_D03G0450 showed the opposite *** functional verification of GH_D03G0451 indicated that the GH_D03G0451-silenced plants showed a delay in the flowering *** results suggest that these are the candidate genes for cotton early maturity,and they may be used for breeding early-maturity cotton varieties.

关键词： cotton genomics early-maturity traits BSA-seq QTl mapping molecular breeding