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Segregation in Vertically Vibrated Binary Granular Mixtures with Same Size

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Chinese Physics Letters 2006年第11期23卷 3080-3083页

作者：史庆藩孙刚厚美瑛陆坤权 Institute of Physics Chinese Academy of Sciences Beijing 100080 Department of Physics Beijing Institute of Technology Beijing 100081

Segregation in vertically vibrated binary granular mixtures with same size is studied experimentally. A new partial segregated state is found in this system. This state exists between the completely mixed state and the pure segregated state, and has the characteristic that the lighter particles tend to rise and form a pure layer on the top of the system while the heavier particles and some of the lighter ones stay at the bottom and form a mixed layer. The ratio of the thickness of the pure top layer and that of the whole system varies continuously with the vibration frequency or amplitude. It is suggested to consider the ratio as an order parameter for describing the degree of the segregation quantitatively. By use of the order parameter, a detailed phase diagram is obtained in Г versus f space. Finally, the formation of the observed partial segregated state is illustrated by the competition between the impact of momentum of the heavier particles and the stiffness of the layer composed of the mixed particles.

关键词： flows SEPARATION AVALANCHES SOLIDS MATTER

Numerical solutions of 2-D steady compressible natural convection using high-order flux reconstruction

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Acta Mechanica Sinica 2019年第2期35卷 401-410页

作者： Yaojie Yu Feng Liu Tingbo Zhou Chao Gao Ya Liu National Key Laboratory of Aerodynamic Design and Research Northwestern Polytechnical UniversityXi’an 710072 China Department of Mechanical and Aerospace Engineering University of California Irvine Irvine CA 92697 USA Facility Design and Instrumentation Institute China Aerodynamics Research and Development CenterMianyang 621000 China

Low Mach number flows are common and typical in industrial applications. When simulating these flows, performance of traditional compressible flow solvers can deteriorate in terms of both efficiency and accuracy. In this paper, a new high-order numerical method for two-dimensional(2-D)state low Mach number flows is proposed by combining flux reconstruction(FR)and preconditioning. Firstly, a Couette flow problem is used to assess the efficiency and accuracy of preconditioned FR. It is found that the FR scheme with preconditioning is much more efficient than the original FR scheme. Meanwhile,this improvement still preserves the numerical accuracy. Using this new method and without the Boussinesq assumption,classic natural convection is directly simulated for cases of small and large temperature differences. For the small temperature difference, a p and h refinement study is conducted to verify the grid convergence and accuracy. Then, the influence of the Rayleigh number (Ra) is analyzed. By comparing with the reference results, the numerical results of preconditioned FR is very close to that calculated by incompressible solvers. Furthermore, a large temperature difference test case is calculated and analyzed, indicating this method is not limited by the Boussinesq assumption and is also applicable to heat convection with large temperature differences.

关键词： Flux reconstruction Preconditioning method Low Mach flows Natural convection

Approximate Analytical Solutions for a Class of Laminar Boundary-Layer Equations

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Chinese Physics Letters 2007年第7期24卷 1981-1984页

作者： Seripah Awang Kechil Ishak Hashim Sim Slaw Jiet Department of Mathematics Univer'siti Teknologi MARA 40450 Shah Alam Selangor Malaysia School of Mathematical Sciences Universiti Kebangsaan Malaysia 43600 UKM Bangi Selangor Malaysia

A simple and efficient approximate analytical technique is presented to obtain solutions to a class of two-point boundary value similarity problems in fluid mechanics. This technique is based on the decomposition method which yields a genera/analytic solution in the form of a convergent infinite series with easily computable terms. Comparative study is carried out to show the accuracy and effectiveness of the technique.

关键词： ADOMIAN DECOMPOSITION METHOD COMPARING NUMERICAL-METHODS GA-SB SYSTEM MARANGONI CONVECTION UNBOUNDED DOMAIN ALGORITHM SURFACE flows

A three-dimensional k-ε-k_p model in curvilinear coordinates for sediment movement and bed evolution

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Science China(Technological Sciences) 2009年第4期52卷 1090-1100页

作者： SHEN YongMing1 & LIU Cheng2 1 State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116023, China 2 Pearl River Hydraulic Research Institute, Guangzhou 510611, China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian China Pearl River Hydraulic Research Institute Guangzhou China

To aim at the substitution of the magnitude and direction of water flow movement near bed for those of bed load transport in solid-liquid two-phase one-fluid model, and to simulate the effect of secondary flow on transverse bed load transport in channel bends and the effect of bed slope on bed load trans- port in a better way, a three-dimensional k-ε-kp solid-liquid two-phase two-fluid model in curvilinear coordinates is solved numerically with a finite-volume method on an adaptive grid for studying wa- ter-sediment movements and bed evolution in a 120° channel bend. Numerical results show that the trajectories of solid-phase deviate from those of liquid-phase in the channel bend, and the deviation increases with the increase of the particle diameters. The calculated bed deformation by the k-ε-kp model is in better agreement with measured bed deformation than those by one-fluid model. It is proved that the k-ε-kp model can simulate the effect of secondary flow on lateral bed load transport with the higher accuracy than the one-fluid model.

关键词： curvilinear coordinates three-dimensional k-ε-kp model two-fluid model solid-liquid flows channel bend bed load bed evolution tra- jectory

Changes of tropical cyclone tracks in the western North Pacific over19792016

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Advances in Climate Change Research 2018年第3期9卷 170-176页

作者： ZHANG Wen-Qian WU Li-Guang ZOU Xu-Kai Pacific Typhoon Research Center Nanjing University of Information Science & Technology Nanjing 210044 China Key Laboratory for Climate Studies National Climate Center China Meteorological Administration Beijing 100081 China

The tropical cyclone （TC） trajectory model has been widely used to investigate the mechanism of the climate change of TC tracks. In thisstudy, the Gaussian weight interpolation method is used to calculate the beta drift in the TC track or trajectory model. By simulating historicalTC tracks, the new calculation can better simulate the spatial distribution of the frequency of TC occurrence. The improved track model isfurther used to understand the TC track change during the period of 1979e2016. In 1979e2016, the TC activity has been suppressed in theSouth China Sea （SCS） while the TC influence along the southeast coastal regions of China has been increased. The sensitivity experimentsindicate that the change of the formation location plays a dominant role in decreasing TC influence in the SCS while the change of theenvironmental steering flows increases the TC influence in the eastern coastal region of China. This study suggests that the ongoing climatechange can affect the TC activity along the coast of China.

关键词： Tropical cyclone Trajectory model Beta drift Formation position Large-scale steering flows

Analyzing Characters of Plasma Wake with Method of Chaos Dynamics

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Chinese Physics Letters 1998年第12期15卷 889-891页

作者： CAO Jin-xiang FANG Jian-dong ZHAO Hong-bo LIN Yi-jun ZHANG Jia-xiang WANG Jie-xia DONG Yong-hui Department of Modern Physics University of Science and Technology of ChinaHefei 230027 Beijing Institute of Aerodynamics Beijing 100074

In this paper,analyzing the experiment data of multiple scanning probes in the arc wind-driven hypersonic plasma flows with the chaos dynamics method,we have obtained the power spectrum,the frequency wavenumber spectral density,the correlation dimension and Kolmogorov entropy of the flows,*** distribution of correlation dimension and Kolmogorov entropy of the blunt cone wakes along the axis and the radius of the flows are presented successfully in the *** distributions clearly show the structure of turbulence and lamination in blunt cone *** the method of minimum Kolmogorov entropy,we observed the structure of the bow shock at far wake region in the blunt cone wakes.

关键词： entropy flows dimension

Phanerozoic magmatism in the Proterozoic Cuddapah Basin and its connection with the Pangean supercontinent

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Geoscience Frontiers 2019年第6期10卷 2239-2249页

作者： Th.Dhanakumar Singh C.Manikyamba Li Tang Sohini Ganguly M.Santosh K.S.V.Subramanyam Arubam C.Khelen CSIR-National Geophysical Research Institute(Council of Scientific and Industrial Research) Uppal RoadHyderabad 500007India School of Earth Sciences and Resources China University of Geosciences Beijing29 Xueyuan RoadBeijing 100083China Department of Earth Sciences Goa UniversityTaleigao PlateauGoa 403206India Centre for Tectonics Exploration and ResearchUniversity of AdelaideAdelaideSA 5005Australia Key Lab of Submarine Geosciences and Prospecting Techniques MOE AND College of Marine GeosciencesOcean University of ChinaQingdao 266100China

Magmatic pulses in intraplate sedimentary basins are windows to understand the tectonomagmatic evolution and paleaoposition of the *** present study reports the U-Pb zircon ages of mafic flows from the Cuddapah Basin and link these magmatic events with the Pangean evolution during late Carboniferous-Triassic/Phanerozoic *** U-Pb geochronology for the basaltic lava flows from Vempalle Formation,Cuddapah Basin suggests two distinct Phanerozoic magmatic events coinciding with the amalgamation and dispersal stages of Pangea at 300 Ma(Late Carboniferous)and 227 Ma(Triassic).Further,these flows are characterized by analogous geochemical and geochronological signatures with Phanerozoic counterparts from Siberian,Panjal Traps,Emeishan and Tarim LIPs possibly suggesting their coeval and cogenetic *** the Phanerozoic Eon,the Indian subcontinent including the Cuddapah Basin was juxtaposed with the Pangean LIPs which led to the emplacement of these pulses of magmatism in the Basin coinciding with the assemblage of Pangea and its subsequent breakup between 400 Ma and 200 Ma.

关键词： Cuddapah Basin Mafic flows Zircon U-Pb geochronology Phanerozoic magmatism Pangea supercontinent

A Characteristic Non-Reflecting Boundary Treatment in Lattice Boltzmann Method

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Chinese Physics Letters 2008年第6期25卷 1964-1967页

作者： KIM Dehee KIM Hyung Min JHON Myung S VINAY Ⅲ Stephen J. BUCHANAN John Department of Chemical Engineering Carnegie Mellon University 5000 Forbes Ave Pittsburgh PA 15213 USA Division of Mechanical System Design Engineering Kyonggi University Suwon Kyonggi-do Korea Bechtel Bettis Inc West Mifflin PA 15122 USA

In lattice Boltzmann methods, disturbances develop at the initial stages of the simulation, the decay characteristics depend mainly on boundary treatment methods; open boundary conditions such as equilibrium and bounce-back schemes potentially generate uncontrollable disturbances. Excessive disturbances originate from non-physical reflecting waves at boundaries. Characteristic boundary conditions utilizing the signs of waves at boundaries which suppress these reflecting waves, as well as their implementation in the lattice Boltzmann method, are introduced herein. The performance of our novel boundary treatment method to effectively suppress excessive disturbances is verified by three different numerical experiments.

关键词： HYPERBOLIC SYSTEMS EQUATION flows

Shear Stress Distribution in the Vicinity of Tilting Disk Heart Valve Model

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Chinese Physics Letters 1997年第1期14卷 28-31页

作者： SUN Yong-da Department of Applied Physics Tianjin UniversityTianjin 300072

The visualizations of pulsatile flows through tilting disk heart valve models were completed by means of the technique of the dynamic flow *** distribution of the fluid shear stresses in the near vicinity of heart val... 详细信息

关键词： Shear flows flow