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25 June 1992, Volume 9 Issue 2 Previous Issue    Next Issue

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A NUMERICAL SIMULATION OF THREE DIMENSIONAL TRANSONIC CASCADE IN VISCID FLOW Huang Dongtao, Shen Mengyu, Chen Yongliang 1992, 9(2): 111-118.  Abstract ( )   PDF (455KB) ( )   This paper presents an unfactored efficient algorithm for 3-D Euler equationsbased on the implicit flux-splitting and the line Gauss-Seidel iteration. In the algorithm the explicit terms on the right side of the discretization equation are treated in second order accuracy and to solve the implicit discretization equation one back-and-forth sweep in the main flow direction is taken and an alternating direction line G-S interation is carried out in the other two directions. The numerical calculations of 3-D transonic cascade inviscid blow tave shown that the algorithm has a quite high convergent rate.

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FE-89 CODE AND SIMULATION OF SOME HIGH-VELOCITY IMPACT PROBLEMS Wang Zixiu, Guo Qin 1992, 9(2): 119-126.  Abstract ( )   PDF (505KB) ( )   In this paper, we briefly introduced the twodimensional finite element code-FE-89 code. A high-velocity impact problem of the composite liner onto the thin-wall cylinder was computed and some qualitative and qualitative results are presented. Besides, the numerical results of a test example are compared with experiment.

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THE FOLLOW-FLOW SCHEMES FOR SOLVING THE CONVECTION-DOMINATED BURGERS EQUATION Jiang Jinliang 1992, 9(2): 127-132.  Abstract ( )   PDF (396KB) ( )   When the convection-dominated Burgers equation is solved by use of the difference method, the computational accuracy of many usual difference schemes will lower.The designre-quirements of difference scheme of the non-linear convection term are presented, and some new difference schemes, which is known as follow-flow schemes, are obtained in this paper, in order to raise the computational accuracy of convection-dominated equation. The advantages of the follow-flow schemes are shown by means of some examples in this paper.

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SIMI-IMPLICIT RUNGE-KUTTA TYPE PARALLEL DIRECT INTEGRATION METHODS FOR STRUCTURAL DYNAMIC PROBLEM Zhou Shuquan, Gao kehua 1992, 9(2): 133-138.  Abstract ( )   PDF (302KB) ( )   This paper presents simiimplicit Runge-kutta type parallel direct integration methods to solve structural dynamic problems using 3-stage-3-order semi-implicit Runge-kutta method and using polynomial preconditioned conjugate gradient method for solving relevant systems of linear algebraic equations. Compared with relevant serical algorithm RK33S on YH-1 computer, parallel algorithm RK33P's speed up is 24~27 when linear systems of equations involved is of order 103~104.

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IMPLICIT ENO SCHEME AND ITS APPLICATIONS ON INTERNAL FLOW PROBLEMS Ma Handong, Ma Yanwen 1992, 9(2): 139-146.  Abstract ( )   PDF (463KB) ( )   In this paper, we present a modified implicit ENO scheme and combine it with CSCM-like implicit supra-characteristic boundary treatment. Numencal experiment with this scheme for 2-D channel fupersonic flow aboat 4% circular arc has damenstrated the sharp shock-capturing capability of the scheme. The results are also compared with those of TVD scheme. The futher application to the viscid flow in simplified inlet is made. They show a good agreelment with the results of SIP/Beam-warming schemes except nearby the reflection point of shock. But our results seem to be more reasonable.

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A FINITE VOLUME METHOD AND MULTIPLE-GRID TECHNIQUE FOR TRANSONIC FLOW FIELDS THROUGH PLANE CASCADES Zhang Yaoke, Qi Changjun 1992, 9(2): 147-153.  Abstract ( )   PDF (411KB) ( )   Since 1982, Ni, Davis et al.have developed a time-dependent finite volume method combined with multiple-grid technique. It is an explicit scheme by which a steady state solution can be obtained rapidly. This paper adopts the method to compute the transonic flow field through plane cascades. First, elementary ideas and treatment principles of Ni-Davis scheme are clarified. The numerical treatments on solid wall boundary are then improved. The artificial viscous terms used are stated. With numerical tests, an improved algorithm for multiple-grid technique is presented. Finally, two examples of transonic flow fields through plane cascades are described. The computational accuracy and efficiency of numerical results are acceptable for aerodynamic design of aero-engine. Computing a steady state solution on a 65×17 grid takes about 15 minutes CPU time on IBM 4341 computer. With multiple-grid scheme, the savings in CPU time is about 50% to 60%.

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AN EFFICIENT ALGORITHM TWO-POINT BOUNDARY VALUE PROBLEMS Huang Zhengming 1992, 9(2): 154-162.  Abstract ( )   PDF (503KB) ( )   This paper deals with the numerical solutions for nonlinear boundary value problems governed by ordinary differential equations. The nonlinear functions are locally linearized sequentially and a shooting method is then applied to the linearilized equations.This technique is found to be faster in numerical convergence compared with a standard shooting method (i. e. when it is applied directly to the original nonlinear equations). A further reduction in computer time expenditure can be made with the utilization of interpolation to the Jacobian matrices. The present method is simple and easy to be programmed. By making use an exchange process technique of the internal storage requirements with the external equipments of a machine, one may analysis, with the present method, a rather large and complicated problem in a personal computer. A numerical example shows that the present method requires much fewer iterative steps to reach convergence than some finite difference scheme combined with Newton's method does.

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A PROGRAM FOR THE ANGULAR MOMENTA AND THEIR MULTIPLICITIES OF IDENTICAL PARTICLE SYSTEM Liu Yuxin 1992, 9(2): 163-168.  Abstract ( )   PDF (367KB) ( )   In this paper, the structure, function and usage as well as the calculation method of a FORTRAN program is described systematically. With the multi-row partition of nonnegative integer being used, the program can efficiently determine the angular monenta and their multiplicites of the identical particle system with well defined seniority.

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SPECTROSCOPIC DATA FOR HIGHLY CHARGED NEON-LIKE IONS Li Shichang, Sun Yongsheng, Han Guoxiang, Yang Hanyang 1992, 9(2): 169-181.  Abstract ( )   PDF (707KB) ( )   The purpose of the present work is to provide the immense amount of atomic data needed for applications to the ICF and X-ray laser research work in our institute and for the compilation-evaluation work in Chinese Research Association for Atomic and Molecular Data. Using the non-relativistic Hartree-Fock self-consistent field method including the relaticistic mass-velocity and Darwin terms in the Hamiltonian (HFR) proposed by Dr.R.Cowan, we have calculated atomic structure data and spectroscopic data for the Neon-like FeⅩ Ⅶ, NiⅪ Ⅹ, CuⅩⅩ,GeⅩⅩ Ⅲ and SeⅩⅩ Ⅴ ions. In the calculations the configuration-interaction effects were taken into account. The configuration average energies, 88 energy levels, all possible electric dipole transition wavelengths, oscillator strengths are presented, and in order to discuss the accuracy of the present results we have also compared them with other works.

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ACCURATE ALGORITHM FOR NUMERICAL SIMULATION OF NONLINEAR STOCHASTIC PROCESS DRIVED BY MULTIPLICATIVE COLORED NOISE Bao Jingdong 1992, 9(2): 182-186.  Abstract ( )   PDF (288KB) ( )   A accurate and fast numerical algorithm is proposed here for solving nonlinear differential stochastic equation with multiplicative colored noise. The stable cases of solution for chosing of time step and trajectory numbers are discussed.

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PARAMETRIC TRANSFORM METHOD DERIVED SOLITON WAVE EQUATION AND SOLITON SOLUTION Shen Tinggen 1992, 9(2): 187-191.  Abstract ( )   PDF (271KB) ( )   In this pater, using parametric transform method direct derive soliton wave equation of loss optical fibers and elementary soliton solution.

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A NUMERICAL COMPARISON FOR ITERATIVE METHODS OF COMPLEX ALGEBRAIC EQUATION SYSTEMS Ma Zeyi 1992, 9(2): 192-196.  Abstract ( )   PDF (312KB) ( )   From the 2-D nonlinear Schrödinger equation, a complex algebraic equation system is obtained. This paper uses Gauss-Seidel, SOR, Complex BI-CG and complex BI-PCG to solve the system and compares the total costs of iterations of these iterative methods. Meanwhile, the complex equation system is also transformed into a real system whose coefficient matrix is hepta-diagonal. Gauss-Seidel, SOR and PCG methods are then used to solve it and the total costs of iterations are also compared. The result shows that the PCG method is most effective comparing with the others. It is discussed as well that how to select the optimal relaxation factor of SOR method for the systems considered.

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STOCHASTIC BOUNDARY CONDITIONS OF MONTE CARLO STATISTICAL PHYSICS Hongdong Zhang, Jianming Lu, Yuliang Yang 1992, 9(2): 197-202.  Abstract ( )   PDF (381KB) ( )   A New type of Boundary condition for the Monte Carlo statical physics, stochastic boundary condition (SBC), has been proposed in this paper. The SBC is tested on the Lebwohl-Lasher model nematogens with 4×4×4 to 16×16×16 particles. Results for the transition temperature from nematic to isotropic and the order parameters are in good agree with those obtained from the simulation of much larger systems. Comparison with the results obtained from the conventional periodic boundary condition (PBC) shows that the SBC approaches the thermodynamic limit (N→∞) much faster than PBC. Terefore, high accuracy is achievable by using SBC with relatively small number of particles. The new boundary condition is fairly general and should be applicable in a variety of simulations.

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A New Interpolation Method for Two-dimensional Functions in Evaluated Nuclear Data Library Cai Shaohui 1992, 9(2): 203-212.  Abstract ( )   PDF (556KB) ( )   Unreasonable spectrum shape is often obtained from a simple Cartesian interpolation scheme for two-dimensional functions. A unified non-Cartesian interpolation scheme which may have no such trouble,has been proposed. Additional data required for the new method have been discussed.

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GEOMETRIC OPTICAL TRANSFER FUNCTION AND TIS COMPUTATION METHOD Wang Qi 1992, 9(2): 213-218.  Abstract ( )   PDF (410KB) ( )   Geometric Optical Transfer Function formula is derived after expound some content to be easily ignored, and the computation method is given with Bessel function of order zero and numerical integration and Spline interpolation. The method is of advantage to ensure accuracy and to save calculation.

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ON THE STUDY OF CALCULATE OF ANALYSIS MASS IN SKYRME MODEL Zhang Shou, Lin Jinhu 1992, 9(2): 219-222.  Abstract ( )   PDF (234KB) ( )   In this paper by means of Reduce Language we study the calculate method of soliton mass in Skyrme model. By computer calculate conclude has showed that the method of matrix and concrete expansion is better than the method of the gereral operator experession.