Table of Content

18 January 2008, Volume 29 Issue 1

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Articles

PSE as applied to problems of secondary instability in supersonic boundary layers

ZHANG Yong-ming;ZHOU Heng

2008, 29(1):  1-8 .  doi:10.1007/s10483-008-0101-7

Abstract ( 1524 )   PDF (409KB) ( 606 )  

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Modal analysis of coupled vibration of belt drive systems

LI Xiao-jun;CHEN Li-qun

2008, 29(1):  9-13 .  doi:10.1007/s10483-008-0102-x

Abstract ( 1192 )   PDF (231KB) ( 844 )  

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The modal method is applied to analyze coupled vibration of belt drive systems. A belt drive system is a hybrid system consisting of continuous belts modeled as strings as well as discrete pulleys and a tensioner arm. The characteristic equation of the system is derived from the governing equation. Numerical results demenstrate the effects of the transport speed and the initial tension on natural frequencies.

Numerical simulation of quasi-streamwise hairpin-like vortex generation in turbulent boundary layer

ZHANG Nan;LU Li-peng;DUAN Zhen-zhen;YUAN Xiang-jiang

2008, 29(1):  15-22 .  doi:10.1007/s10483-008-0103-z

Abstract ( 1325 )   PDF (345KB) ( 702 )  

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Some integral inequalities on time scales

Adnan Tuna;Servet Kutukcu

2008, 29(1):  23-29 .  doi:10.1007/s10483-008-0104-y

Abstract ( 1340 )   PDF (156KB) ( 989 )  

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In this article, we study the reverse Hölder type inequality and Hölder inequality in two dimensional case on time scales. We also obtain many integral inequalities by using Hölder inequalities on time scales which give Hardy's inequalities as spacial cases.

Nonlinear turbulence models for predicting strong curvature effects

XU Jing-lei;MA Hui-yang;HUANG Yu-ning

2008, 29(1):  31-42 .  doi:10.1007/s10483-008-0105-z

Abstract ( 1539 )   PDF (587KB) ( 656 )  

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Prediction of the characteristics of turbulent flows with strong streamline curvature, such as flows in turbomachines, curved channel flows, flows around airfoils and buildings, is of great importance in engineering applications and poses a very practical challenge for turbulence modeling. In this paper, we analyze qualitatively the curvature effects on the structure of turbulence and conduct numerical simulations of a turbulent U-duct flow with a number of turbulence models in order to assess their overall performance. The models evaluated in this work are some typical linear eddy viscosity turbulence models, nonlinear eddy viscosity turbulence models (NLEVM) (quadratic and cubic), a quadratic explicit algebraic stress model (EASM) and a Reynolds stress model (RSM) developed based on the second-moment closure. Our numerical results show that a cubic NLEVM that performs considerably well in other benchmark turbulent flows, such as the Craft, Launder and Suga model and the Huang and Ma model, is able to capture the major features of the highly curved turbulent U-duct flow, including the damping of turbulence near the convex wall, the enhancement of turbulence near the concave wall, and the subsequent turbulent flow separation. The predictions of the cubic models are quite close to that of the RSM, in relatively good agreement with the experimental data, which suggests that these models may be employed to simulate the turbulent curved flows in engineering applications.

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ZHANG Zhi-guo;LI Jun-feng

2008, 29(1):  43-50 .  doi:10.1007/s10483-008-0106-x

Abstract ( 1323 )   PDF (263KB) ( 1319 )  

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YANG Ya-zheng;YANG Jia-ling;FANG Dai-ning

2008, 29(1):  51-60 .  doi:10.1007/s10483-008-0107-1

Abstract ( 1260 )   PDF (264KB) ( 1639 )  

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Solution of nonlinear wave equation of elastic rod

GUO Peng;ZHANG Lei;Lü Ke-pu;DUAN Wen-shan

2008, 29(1):  61-66 .  doi:10.1007/s10483-008-0108-y

Abstract ( 1421 )   PDF (179KB) ( 475 )  

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ZHAO Xue-chuan;LEI Yong-jun;ZHOU Jian-ping

2008, 29(1):  67-74 .  doi:10.1007/s10483-008-0109-x

Abstract ( 1377 )   PDF (342KB) ( 440 )  

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MENG Xin-zhu;ZHAO Qiu-lan;CHEN Lan-sun

2008, 29(1):  75-87 .  doi:10.1007/s10483-008-0110-x

Abstract ( 1406 )   PDF (248KB) ( 807 )  

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Interaction of underwater explosion bubble with complex elastic-plastic structure

ZHANG A-man;YAO Xiong-liang

2008, 29(1):  89-100 .  doi:10.1007/s10483-008-0111-z

Abstract ( 1415 )   PDF (438KB) ( 966 )  

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Algorithm for phase contrast X-ray tomography based on nonlinear phase retrieval

NI Wen-lei;ZHOU Tie

2008, 29(1):  101-112 .  doi:10.1007/s10483-008-0112-8

Abstract ( 1144 )   PDF (340KB) ( 457 )  

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A new algorithm for phase contrast X-ray tomography under holographic measurement was proposed in this paper. The main idea of the algorithm was to solve the nonlinear phase retrieval problem using the Newton iterative method. The linear equations for the Newton directions were proved to be ill-posed and the regularized solutions were obtained by the conjugate gradient method. Some numerical experiments with computer simulated data were presented. The efficiency, feasibility and the numerical stability of the algorithm were illustrated by the numerical experiments. Compared with the results produced by the linearized phase retrieval algorithm, we can see that the new algorithm is not limited to be only efficient for the data measured in the near-field of the Fresnel region and thus it has a broader validity range.

Some discrete SI and SIS epidemic models

LI Jian-quan;LOU Jie;LOU Mei-zhi

2008, 29(1):  113-119 .  doi:10.1007/s10483-008-0113-y

Abstract ( 1342 )   PDF (170KB) ( 1334 )  

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The probability is introduced to formulate the death of individuals, the recovery of the infected individuals and incidence of epidemic disease. Based on the assumption that the number of individuals in a population is a constant, discrete-time SI and SIS epidemic models with vital dynamics are established respectively corresponding to the case that the infectives can recover from the disease or not. For these two models, the results obtained in this paper show that there is the same dynamical behavior as their corresponding continuous ones, and the threshold determining its dynamical behavior is found. Below the threshold the epidemic disease dies out eventually, above the threshold the epidemic disease becomes an endemic eventually, and the number of the infectives approaches a positive constant.

An analytical expression of reliability solution for Druker-Prager criterion

ZHANG Lang;LIU Dong-sheng;SONG Qiang-hui;LIU Shan-wen

2008, 29(1):  121-128 .  doi:10.1007/s10483-008-0114-z

Abstract ( 1352 )   PDF (383KB) ( 519 )  

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Strength parameters of rock mass are taken as random variables. Based on the reliability theory, an analytical expression of reliability solution for Drucker-Prager criterion is given. The Monte-Carlo method and FORM (first order reliability method) are used to test the correctness of the solution. Some influences of variation of strength parameters on the judging results of Drucker-Prager criterion are discussed by the use of the solution. Conclusions of discussion show that variations of strength parameters have different influences on the reliability probability of Drucker-Prager criterion. When the coefficients of variation of strength parameters are great, their influences on the reliability probability of Drucker-Prager criterion are obvious and can not be neglected. The conclusions of this paper provide a new way for the reliability judgment of yield on rock mass.

Using reproducing kernel for solving a class of partial differential equation with variable-coefficients

WANG Yu-lan;CHAO Lu

2008, 29(1):  129-137 .  doi:10.1007/s10483-008-0115-y

Abstract ( 1439 )   PDF (203KB) ( 943 )  

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How to solve the partial differential equation has been attached importance to by all kinds of fields. The exact solution to a class of partial differential equation with variable-coefficient is obtained in reproducing kernel space. For
getting the approximate solution, give an iterative method, convergence of the iterative method is proved. The numerical example shows that our method is effective and good practicability.