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High order finite volume methods for singular perturbation problems

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Science China Mathematics 2008年第8期51卷 1391-1400页

作者： CHEN ZhongYing HE ChongNan WU Bin Department of Scientific Computing and Computer Applications Sun Yat-Sen UniversityGuangzhou 510275China College of Mathematics and Computer Science Guangxi University for NationalitiesNanning 530006China

In this paper we establish a high order finite volume method for the fourth order singular perturbation problems.In conjunction with the optimal meshes,the numerical solutions resulting from the method have optimal co... 详细信息

关键词： finite volume methods optimal meshes singular perturbation problems

Numerical simulation on centrifugal pump compressible flow field with different gas volume fractions

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排灌机械工程学报 2019年第2期37卷 106-111,129页

作者： WANG Like LIAO Weili LU Jinling LUO Xingqi RUAN Hui ZHAO Yaping WANG Jing Institute of Water Resource and Hydro-electric Engineering Xi'an University of Technology

In order to study the influence of gas-liquid two-phase flow on the performance and internal flow field of a centrifugal pump,the steady three-dimensional flow with different gas volume fractions was simulated by applying the Reynolds-average N-S equation and mixture gas-liquid two-phase flow model,and the compressibility of gas was taken into consideration in the simulation. Then the centrifugal pump characteristic and the gas distribution law in different gas volume fractions were analyzed. The computational results show that gas volume fraction has a certain influence on the performance of the centrifugal pump,and the efficiency and head of the pump are on the decline with the increase of it.Static pressure in the impeller increases in the radial direction,but the pressure gradient in the flow direction is different under the different gas volume fractions. The gas volume is distributed mainly in the ipsilateral direction of impeller back shroud in the flow channel of the volute. On the suction side of the blade inlet there is an obvious low-pressure area,which causes bubbles agglutination and higher gas volume fraction. With the gas entering passage flow,gas volume fraction in the suction decreases and the pressure surface rises gradually. Higher gas volume fraction causes air blocking phenomenon in the flow passage and the discharge capacity reduces. The increase of gas volume makes the turbulent motion within the impeller more and more intense,which leads to more and more energy loss.

关键词： centrifugal pump Mixture model gas-liquid two-phase flow gas volume fraction compressibility

Quality measures of reconstruction filters for stereoscopic volume rendering

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Computational Visual Media 2016年第1期2卷 19-30页

作者： David A.T.Roberts Ioannis Ivrissimtzis School of Engineering and Computing Sciences Durham University

In direct volume rendering(DVR), the choice of reconstruction filter can have a significant effect on the visual appearance of the images produced and thus, on the perceived quality of a DVR rendered scene. This paper presents the results of a subjective experiment where participants stereoscopically viewed DVR rendered scenes and rated their subjective quality.The statistical analysis of the results focuses on the relationship between the quality of the stereoscopic scene and properties of the filters such as post-aliasing and smoothing, as well as the relationship between the quality of the stereoscopic scene and properties of the rendered images such as shape compactness.The experiment evaluated five reconstruction filters on four different volumetric datasets. Participants rated the stereoscopic scenes on four quality measures:depth quality, depth layout, lack of jaggyness, and sharpness. The results show that the correlation between the quality measures and post-aliasing and smoothing, which are properties associated with each reconstruction filter, is moderate and statistically insignificant. On the other hand, the correlation between the quality measures and compactness, which is a property specific to each rendered image, is strong and statistically significant.

关键词： direct volume rendering(DVR) reconstruction filters stereoscopic user evaluations

A class of the fourth order finite volume Hermite weighted essentially non-oscillatory schemes

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Science China Mathematics 2008年第8期51卷 1549-1560页

作者： ZHU Jun QIU JianXian Department of Mathematics Nanjing UniversityNanjing 210093China College of Science Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In this paper,we developed a class of the fourth order accurate finite volume Hermite weighted essentially non-oscillatory(HWENO)schemes based on the work(Computers&Fluids,34:642-663(2005))by Qiu and Shu,with Total Variation Diminishing Runge-Kutta time discretization method for the two-dimensional hyperbolic conservation laws.The key idea of HWENO is to evolve both with the solution and its derivative,which allows for using Hermite interpolation in the reconstruction phase,resulting in a more compact stencil at the expense of the additional work.The main difference between this work and the formal one is the procedure to reconstruct the derivative terms.Comparing with the original HWENO schemes of Qiu and Shu,one major advantage of new HWENOschemes is its robust in computation of problem with strong shocks.Extensive numerical experiments are performed to illustrate the capability of the method.

关键词： finite volume HWENO scheme conservation laws Hermite polynomial TVD RungeKutta time discretization method

AN INVESTIGATION OF THE RELATION BETWEEN COTTON FIBRE PROPERTIES AND YARN QUALITY BY USING HIGH volume INSTRUMENT(HVI)SYSTEM

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Journal of China Textile University(English Edition) 1993年第2期10卷 7-13页

作者： M.A.Zaman 储才元严灏景 Dept.of Textile Engineering

The objective of this paper is to establish reliable prediction equations relating cotton fibreproperties measured by HVI system and yarn quality,A useful statistical method is adopted for de-veloping a multiple regression model interpreting the relation between the data of Spinlab HVIfibre properties and quality parameters of yarn STQ (Strength Tex Quotient).The percent relativecontribution of a fibre property with respect of STQ is also assessed.The results show that the totalcontribution of the HVI measured fibre properties can account for 77.4% of known variation ofyarn STQ.The main feature of the approach is its flexibility in accommodating all fibre properties.The examination of regression equation showed that it could be well applied to predict STQ ofyarns spun from the same spinning system,but,for different spinning systems and also for yarns ofdifferent linear density,modification of the equation would be needed.

关键词： regression analysis correlations cotton fibres fibre properties cotton yarn yarn properties ring spinning High volume Instrument

Evaluating volume Fractions of the Elements for Composite Laminates by Using Dielectric Properties

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Journal of Donghua University(English Edition) 2001年第1期18卷 59-63页

作者：周胜储才元严灏景 Coll. of Textiles Dong Hua Univ. Shanghai 200051 China

A series and parallel model for investigating the capacity of composite laminates and the relationship between the dielectric properties of the composites and its constituents are presented. volume fractions of the constituents are considered in this study. The expression of the complex dielectric constants for evaluating volume fractions under discrete frequencies is established and the general solutions for the resultant linear simultaneous equations for system are also exploited.The results show that the high accuracy of proposed method is obtained.

关键词： composite laminate, volume fraction, dielectric constant.

Compositional variation and volume loss of a shear zone——Hetai shear zone as a case history

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Chinese Science Bulletin 1995年第19期40卷 1638-1641页

作者：钟增球游振东 China University of Geostienoes Wuhan 430074 China

In a shear zone, being a defect within the earth crust, there must be a coupling of thermal, mechanical, chemical and fluidal processes. The chemical disequilibrium and component migration caused by strain localization and mechanical instability induce the readjustment of chemical compositions within a shear zone. There are different ways of interpretation for chemical element enrichment and depletion within a shear zone. Howev-

关键词： Hetai shear zone compositional variation volume loss fluid/rock ratio.

Friction effect on free volume in amorphous-crystal region of PTFE

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Chinese Science Bulletin 1997年第13期42卷 1079-1082页

作者： Yan, FY Xue, QJ Wang, WH CHINESE ACAD SCI LANZHOU INST CHEM PHYSLAB SOLID LUBRICATLANZHOU 730000PEOPLES R CHINA

POSITRON annihilation technique (PAT) is a sensitive probe to detect the size and concentrationof free volume holes. In recent years, it has been used to study the correlation between mi-crostructure and macroscopic properties of crystal polymers. Experimental results show thatthe polymers’ macroscopic properties, such as mechanical properties, thermal properties andstructural phase transition, can be reflected by the change of free volume. It

关键词： fretting free volume interface PTFE.

OSTWALD COARSENING UNDER CHANGING volume FRACTION CONDITION

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中国有色金属学会会刊：英文版 1995年第1期5卷 67-70页

作者： Zhao Jiuzhou Guo, Jingjie Jia Jun Li Qingchun(College of Materials Science and Engineering,Harbin institute of Technology, Harbin 15000l) HARBIN INST TECHNOL COLL MAT SCI & ENGNHARBIN 150001PEOPLES R CHINA

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关键词： Ostwald coarsening second phase volume fraction