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25 March 2010, Volume 27 Issue 2 Previous Issue    Next Issue

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LDDRK Schemes Based on DCS5 Scheme MAO Meiliang, JIANG Yi, DENG Xiaogang 2010, 27(2): 159-167.  Abstract ( )   PDF (385KB) ( )   Based on the fifth order dissipative compact spatial finite difference scheme(DCS5) and the seven stage Runge-Kutta time integration scheme, with the principle that numerical amplification factor approaches the real amplification factor optimally, an optimal methodology for time integration scheme is proposed and a seven stage fifth order LDDRK scheme is obtained. Numerical results of onedimensional wave propagation obtained by convection equation and linearized Euler equations show that the proposed LDDRK scheme has lower dissipation than standard Runge-Kutta schemes.

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Kelvin-Helmholtz Instability in NND Scheme WANG Lifeng, FAN Zhengfeng, YE Wenhua, LI Yingjun 2010, 27(2): 168-172.  Abstract ( )   PDF (279KB) ( )   Kelvin-Helmholtz instability is carried out with local Steger-Warming flux splitting method and NND scheme for hydrodynamic equations. Linear growth rates agree well with linear stability analysis. The method provides clear interface deformation images.

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Simulation of Dam-break Flow with SPH Method YANG Xiufeng, PENG Shiliu 2010, 27(2): 173-180.  Abstract ( )   PDF (723KB) ( )   A smoothed particle hydrodynamics (SPH) method for turbulence is used to simulate dam-break flows. Several 2D and 3D dam-break flows are simulated. For turbulent effects, Reynolds-averaged Navier-Stokes equation together with eddy viscosity assumption are used. SPH results are in good agreement with reported experimental results.

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Detonation Diffraction Simulation with Lagrangian Program in a Desensitization Model LIN Wenzhou, HONG Tao, LIN Zhong, WANG Ruili 2010, 27(2): 181-189.  Abstract ( )   PDF (708KB) ( )   High-energy explosive detonation diffraction is simulated with a 2D Lagrangian unstructured mesh detonation fluid program. With EOS of JWL and trinomial reaction rate, numerical result by Lagrangian program agrees with experimental result qualitatively. Phenomena of whirlpool is well simulated. Desensitization is added to reaction rate in simulation of dead zone in insensitive high explosives detonation diffraction. The dead zone is captured. The result agrees with reported data qualitatively.

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Effect of Pressure and Shock Wave Risetime on Material Ejection LIU Chao, WANG Pei, QIN Chengsen, FENG Qijing, LIANG Xianhong 2010, 27(2): 190-194.  Abstract ( )   PDF (223KB) ( )   A two-dimensional elastic and plastic hydrodynamics code MEPH is applied to simulate ejecting process. We focus on the effect of shock pressure and shock risetime on mass ejection from shocked aluminum. It shows that with increase of shock pressure the ejecting factor keeps increasing, but the ejecting factor is not sensitive to the shock pressure. The effect of shock risetime on the mass ejection from shocked aluminum is also investigated. Numerical results agree well with experiments. The mass ejection is sensitive to shock risetime.

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Constructing Dislocation Atom Distribution withContinuous Dislocation Theory LU Guo, FANG Buqing, ZHANG Guangcai 2010, 27(2): 195-202.  Abstract ( )   PDF (709KB) ( )   A method constructing atom distribution of dislocation configurations based on dislocation theory of continuous medium is presented. Theoretically, this method can be used to construct dislocations with any shape and any Burgers vector. For verification purpose, we construct a linear edge perfect dislocation with Burgers vector b=[110]/2 and a partial dislocation ring with b=[112]/6 in FCC copper. Decomposition process of a edge perfect dislocation and contraction of a partial dislocation ring driven by self-force is simulated. Simulation results agree well with theoretical analysis. The method shows significant superiority in constructing glissile dislocation loops which are generally difficult in other schemes.

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A Coupling Model of Low Permeability Reservoir and Fractured Horizontal Wellbore in Nonsteady State LIAN Peiqing, CHENG Linsong, CAO Renyi, HUANG Shijun 2010, 27(2): 203-210.  Abstract ( )   PDF (378KB) ( )   An unsteady model of fractured horizontal wellbore coupling with a box-shaped reservoir is constructed with consideration of anisotropy in a low permeability reservoir. Solution of the model is shown. Pressure drops of friction and acceleration are considered under different types of constraints. Flow condition in fractured horizontal well is divided into early transient period and pseudo-steady period. In transient period, the output from each fracture differs little, and total production rate increases linearly with fracture number. In pseudo-steady phase, production rate of fractures at the toe and heel is higher than that in the middle. Fractures in symmetrical position have different yield due to frictional and accelerational pressure drops. Pressure loss along the wellbore results in decrease of production in horizontal well and non-uniform distribution of pressure in wellbore. Under constant flow rate followed by constant bottom-hole pressure constraints, production plateau stays longer with increase of fracture number.

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Numerical Simulation on Inhibitory Effects of Angiostatin on Metastasic Tumor Angiogenesis ZHAO Gaiping, CHEN Eryun, SHEN Lixing, WU Jie, XU Shixiong 2010, 27(2): 211-216.  Abstract ( )   PDF (444KB) ( )   We present 2D and 3D discrete mathematical models for migratory response of endothelial cells inside and outside a metastasic tumor based on a physiological fact that some primary tumor can inhibit metastasic tumor growth quickly. In models we consider inhibitory effects of angiostatin excreted by primary tumor, chemotactic effects of TAF due to metastasic tumor and random movement of endothelial cells and simulate spatiotemporal evolution of microvascular network inside and outside the metastasic tumor. It shows that the angiostatin excreted by primary tumor has obviously inhibitory effects on vascular growth rates, bifurcation amount and development of microvascular network inside and outside the metastasic tumor. Inhibitory effects of angiostatin decrease revascularization of a metastasic tumor and suppress growth of the metastasic tumor in tumor therapy. It provides theoretical references for experimental research on clinical anti-angiogenesis.

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Numerical Simulation on Heterogeneous Heat Transfer in Water at Supercritical Pressures in Inclined Upward Tubes LEI Xianliang, LI Huixiong, YU Shuiqing, REN Dalong 2010, 27(2): 217-228.  Abstract ( )   PDF (940KB) ( )   Numerical simulation on flows and heat transfer of water at supercritical pressures in inclined upward smooth tubes of Φ32 mm×3 mm at an angle of 20° respect to the horizon is made. Length of the tube is 8 000 mm. Influence of violent variation of water properties in the so-called "large specific heat region" on heat transfer characteristics was investigated. Numerical method was validated by comparing numerical results with experimental data. Variation of the inner surface temperature of tube wall with enthalpy of water, mass flow rate and heat flux were obtained at pressures of 26 MPa and 34 MPa, respectively. It was found that distributions of wall temperature, as well as heat flux, along tube wall's circumference were non-uniform. Difference between top generatrix wall temperatures and the bottom generatrix wall temperature was analyzed. Effect of water properties in the so-call "large specific heat region" on heat transfer of water was also discussed. Two parameters, namely cross-section transverse kinetic energy and cross-section relative transverse kinetic energy were introduced to quantitatively describe intensity of secondary flow. And density grads along a cross-section perpendicular bisector were used to analysis secondary flow. Abnormal mechanism of inner wall temperature distribution in a large specific region in inclined upward tubes at supercritical pressures was discussed.

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Numerical Simulation of Bluff-body Stabilized Turbulent Non-premixed Flame:A Comparison of Combustion Models HUANG Qing, ZHU Minming, YE Taohong, CHEN Yiliang, DONG Gang 2010, 27(2): 229-239.  Abstract ( )   PDF (549KB) ( )   A joint-scalar probability density function (PDF) method, a steady laminar flamelet model, a Eulerian unsteady laminar flamelet model and a hybrid RANS and PDF method are employed in calculating a bluff-body stabilized turbulent non-premixed Sydney flame HM1. Nitrogen oxides emission is numerically simulated with the joint-scalar PDF method and the Eulerian unsteady laminar flamelet model in order to investigate influence of combustion models on the formation of nitrogen oxides. Comparisons between numerical results and experimental data show that chemical reactions by PDF are best while the computational cost is expensive. The laminar flamelet model results shows lower computational cost and are reasonable in complete combustion.

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Improved Perturbation Approach and Fast Wavelet Galerkin BEM for Capacitance Extraction XIAO Jinyou, CAO Yanchuang, TAUSCH Johannes, ZHANG Duo 2010, 27(2): 240-244.  Abstract ( )   PDF (317KB) ( )   We describe an improved perturbation approach for electrostatic analysis of three-dimensional structures consisting of dielectrics with high-permittivity ratios. Unlike original perturbation approach, the new approach uses only one system matrix with different right hand sides. A fast wavelet Galerkin boundary element method (WGBEM) is used to solve integral equations. Compared with wavelets defined in parameter spaces in a conventional WGBEM, the wavelets here are directly constructed on usual boundary element triangulation. It enables the proposed WGBEM to solve electrostatic problems in complicated geometries, unstructured meshes and comparatively coarse discretizations. Numerical results show that the improved perturbation approach combined with WGBEM has high accuracy and almost linear computational complexity.

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Vegetation Infrared Simulation with Porous Material JIANG Lifeng, YE Hong 2010, 27(2): 245-250.  Abstract ( )   PDF (353KB) ( )   Based on comparability of porous material seepage flow and surface evaporation with plant leaf transpiration, a kind of porous material artificial leaf is proposed. Models of artificial leaf and realistic leaf are set. Influence of porosity, thickness and particle diameter of the artificial leaf on surface temperature is discussed. According to simulation under representative ambient conditions, we found that an artificial leaf with thickness of 0.5 cm, porosity of 0.05 and particle diameter of 2.5 mm is able to simulate infrared characteristics of a realistic leaf. Surface temperature difference is within 3℃ in a day.

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Numerical Study on Infrared Radiation of Photo-elastic Material Subjected to External Loading WANG Fang, LI Yingjun, ZHANG Guangcai, TANG Lian, LONG Zhifei 2010, 27(2): 251-256.  Abstract ( )   PDF (387KB) ( )   Based on thermodynamics and energy conservation law, an elastic body physical model is established. A physical equation of infrared radiation temperature and radiant exitance is achieved. With finite element method(FEM) the model can be used to analyzing infrared radiant energy of a three-point bending beam of elastic-photo material subjected to external loading in room-temperature. It shows that results calculated are highly coincidence with those of experiments. The model and relative theories are rational in quantitative analysis. A quantitative method is shown to analyse and reveal mechanism of infrared radiation of solid materials by computer.

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Laser Induced Sound in Transparent Liquids WANG Yuhong, WANG Jiang'an, WU Ronghua 2010, 27(2): 257-262.  Abstract ( )   PDF (290KB) ( )   Specific acoustic impedance of transparent liquid, sound transmitting distance of laser induced sound and laser beam waist radius are analyzed. It shows that the peak pressure, dominant frequency and energy of laser induced sound increase as specific acoustic impedance increases. The dominant frequency quickly drops in a short distance and then becomes a constant at a larger distance. Under the condition of optical breakdown, a high ratio of laser to sound energy conversion can be obtained with a large laser beam waist radius.

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High Order Finite-element Method Combined withLocally-conformal PML for Electromagnetic Scatterings ZHU Jian, GAN Hui, FAN Zhenhong, CHEN Rushan 2010, 27(2): 263-268.  Abstract ( )   PDF (290KB) ( )   Locally conformal perfectly matched layer (PML) is extended to a high order FEM combined with curvilinear elements and high order basis functions, which proves accuracy and efficiency. It is able to handle challenging geometries with arbitrary curvatures with few unknown numbers, especially those with curvature discontinuities. Validity of the proposed method is demonstrated.

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An MoM-SBR/PO Hybrid Method for Scattering by Complex Objects GENG Fangzhi, PENG Shirui, QIN Kaibing, PAN Yingfeng, SUN Hongwei 2010, 27(2): 269-273.  Abstract ( )   PDF (231KB) ( )   For electromagnetic scattering of 3-D complex electrically large conducting targets,a new hybrid method MoM-SBR/PO is presented to calculate multi-reflection contribution in the PO region, by introducing SBR method that based on Ray-Density Normalization (RDN). Complex matrix multiplication procedure is avoided in this method. Finally, numerical results are presented and compared with reference MoM2D solutions in order to illustrate accuracy and efficiency of the proposed approach.

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Three-dimensional Modeling of Frequency Sounding in Layered Anisotropic Earth Using Integral Equation Method CHEN Guibo, WANG Hongnian, YAO Jingjin, HAN Ziye 2010, 27(2): 274-280.  Abstract ( )   PDF (546KB) ( )   We carry out three-dimensional(3-D) modeling of frequency electromagnetic sounding in layered anisotropic earth using integral equation method. A integral equation formulation is derived based on modified Green's operator with norm less or equal to one. The integral equation is convergent for any conductivity distribution and frequency if iterative solvers are used. An optimal choice method on initial guess for iterative solvers is introduced. It improves computational efficiency of 3-D modeling of frequency electromagnetic sounding significantly. Apparent resistivity responses of 3-D axial frequency electromagnetic sounding are considered in multilayered anisotropic earth.

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Traveltime Computation Using Fast Marching Method Under Complex Topographical Conditions SUN Zhangqing, SUN Jianguo, HAN Fuxing 2010, 27(2): 281-286.  Abstract ( )   PDF (562KB) ( )   Conventional fast marching method (FMM) is improved for traveltime computation. A non-equidistant difference scheme is used to carry local traveltime computation near surface and interface. New grid node type is used to realize narrow band technique under irregular boundary conditions. Analysis on accuracy, efficiency and numerical tests shows that the new method has high-accuracy and accuracy of the reflection wave is higher than that of the first-arrival wave. The new method does not need too more additional computing capacity in dealing with irregular boundaries. The new method can treat strong topographical change, near-surface and subsurface complex media effectively and flexibly. The results consist with laws of wave propagation under complex topographical conditions.

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Numerical Investigation on Fundamental Mode of PBG-PCFwith Full-vector Plane Wave and Multipole Method TANG Bingshu, SHEN Tinggen, WANG Gang 2010, 27(2): 287-292.  Abstract ( )   PDF (435KB) ( )   Numerical investigation on fundamental mode of PBG-PCF with six-fold rotation symmetry is carried out with full-vector plane wave and multipole method. Band gap of two-photonic crystal, constituting PBG-PCF, is determined by full-vector plane wave method. Frequency of possible existing fundamental modes(bound modes) are not only in band gap but also above line k0α=βα. Radiation modes exist out of band gap. Multipole method is performed with input frequency as variables. Field distribution of fundamental mode is plotted by MATLAB. It indicates that fundamental modes do not exist in all possible domains. It gives a feasible method to find fundamental modes of PBG-PCF.

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Electronic Properties of Mn Doping ZnS(001) Surfaces LI Lei, LI Dan, LIU Shiyong, ZHAO Yi 2010, 27(2): 293-298.  Abstract ( )   PDF (369KB) ( )   First principle calculations are made to study formation energies, partial DOS and magnetic moment of three typical surfaces of ZnS(001):Mn. Two interstitial locations are found more stable as comparing formation energies of Mn at three different locations on ZnS(001):Mn surface. Density of states and electron charge density of three reconstructions in ZnS(001):Mn surface are analyzed. It is found that p-d hybridization between spin up Mn-3d and S-3p orbital exists in three ZnS(001):Mn surface models. The p-d mixing is the strongest as Mn is at substituted location. Since spin down Mn-3d states are relatively local, it is shown that mixing between spin down Mn-3d and S-3p is less. Magnetic moments per supercell are calculated for three surfaces.

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LS Coupling and Concise Eigenfunctions of Atomic States:Schaefer and Harris' Method DAI Lili, XIONG Zhuang, CHEN Congyan 2010, 27(2): 299-303.  Abstract ( )   PDF (247KB) ( )   With Schaefer and Harris method, i.e., constructing LS eigenfunctions by diagonlization of L2+λS2, a FORTRAN code with two modes is developed to calculate the most concise LS eigenfunctions under certain symmetry and all LS coupling atomic states (both non-equivalent and equivalent electronic configurations) with given orbital occupancy. As an example, LS coupling atomic states and the simplest LS eigenfunctions for 6I symmetry of Np (Z=93) 5f46d electronic occupancy are calculated.

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Dynamical Study on Interaction of Bose-Einstein Condensates SUN Wenjing, LI Bin, HUA Wei, LIU Xueshen 2010, 27(2): 304-308.  Abstract ( )   PDF (247KB) ( )   Symplectic method is applied to solve numerically 1D time-dependent Gross-Pitaevskii equation. "Breathing" of the condensate is numerically illustrated. Interaction of two Bose-Einstein condensates is investigated as external potential is zero at t=0. Interference between two condensates is observed. Evolution of density due to interference at various relative phases is studied.

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Painlevé Property, Bäcklund Transformation and Soliton Fusion of Nonlinear Vibrating String Equation XU Shujiang, JIANG Lu, GUO Yucui 2010, 27(2): 309-316.  Abstract ( )   PDF (425KB) ( )   With WTC algorithm developed by Weiss, Tabor and Carnevale, we concluded that a nonlinear vibrating string equation has Painlevé property. Bäcklund transformation is obtained. Furthermore, soliton fusion is analyzed by means of Hirota's direct method and Bäcklund transformation.