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New turbulence modeling for air/water stratified flow

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Journal of Ocean Engineering and Science 2020年第1期5卷 55-67页

作者： M.Ghafari M.B.Ghofrani Department of Energy Engineering Sharif University of TechnologyAzadi Ave.TehranIran

The prediction of interfacial turbulence characteristics is one of the still challenging of two-phase stratified flow.The evaluation of some important parameters such as interfacial heat transfer coefficient based on turbulence kinetic energy and turbulence dissipation rate in some models,intensifies the importance of turbulence flow correct simulation.High gradient of velocity and turbulence kinetic energy at the interface of two-phase stratified flow leads to a major overestimation or underestimation of flow characteristics without any special treatment.Consideration of a Source function of turbulence eddy frequency at the interface is one of the common solution employed in past researches.Although this solution remedies some shortcomings of traditional methods in smooth stratified flow,its application in wavy stratified flow needs the other modifications.The examination of turbulence characteristics near the free surface reveals that,in addition to turbulence eddy frequency,the other Source function of turbulence kinetic energy should be considered near the free interface.So,a new Source function of turbulence kinetic energy is proposed at the interface based on flow condition.This new method has been employed for Fabre et al.(1987)experiment designed for air/water stratified flow.The results of simulation have a good agreement with experimental data and turbulence characteristic can be captured near the free surface.

关键词： Stratified flow Turbulence model Turbulence kinetic energy Source function

Imaging source with Gaussian proper time distribution

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维普期刊数据库

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Chinese Physics C 2009年第8期33卷 661-665页

作者：陈丽珠柯宏伟吴元芳 Institute of Particle Physics Huazhong Normal University

Making use of the maximum entropy method, we study the most probable Source function in heavy ion collisions. An anisotropic Gaussian source is deduced by simply assuming that the particles are emitted within a finite proper-time. The general relations between the most probable Source function and the minimal assumptions are discussed, which are instructive in constructing a self-consistent Source function from observed Hanbury-Brown/Twiss（HBT） correlations.

关键词： HBT correlation Source function the maximum entropy method proper-time distribution

Energy budget of surface waves in the global ocean

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Acta Oceanologica Sinica 2009年第3期28卷 5-10页

作者： TENG Yong YANG Yongzeng QIAO Fangli LU Jing YIN Xunqiang First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Key Laboratory of Marine Science and Numerical Modeling State Oceanic Administration Qingdao 266061 China

Mechanical energy input from atmosphere and losses from wave-breaking dissipation of sea surface waves are estimated by a direct scheme. This scheme is based on the integration in the wavenumber space of the wind input and breaking dissipation Source functions of the MASNUM wave model. The global amount of wind energy input, averaged in 2005, is about 57 TW, and the wave-breaking dissipation summed in deep-water is about 33 TW, over a half of the wind energy input. The residual may be dissipated by beach processes. Global distributions of the energy input and breaking dissipation concentrate in the westerlies of the Southern Hemisphere.

关键词： wind energy input wave-breaking dissipation Source function

THE MESHLESS VIRTUAL BOUNDARY METHOD AND ITS APPLICATIONS TO 2D ELASTICITY PROBLEMS

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Acta Mechanica Solida Sinica 2007年第1期20卷 30-40页

作者： Sun Haitao Wang Yuanhan School of Civil Engineering and Mechanics Huazhong University of Science and Technology Wuhan 430074 China

A novel numerical method for eliminating the singular integral and boundary effect is processed. In the proposed method, the virtual boundaries corresponding to the numbers of the true boundary arguments are chosen to be as simple as possible. An indirect radial basis function network （IRBFN） constructed by functions resulting from the indeterminate integral is used to construct the approaching virtual Source functions distributed along the virtual boundaries. By using the linear superposition method, the governing equations presented in the boundaries integral equations （BIE） can be established while the fundamental solutions to the problems are introduced. The singular value decomposition （SVD） method is used to solve the governing equations since an optimal solution in the least squares sense to the system equations is available. In addition, no elements are required, and the boundary conditions can be imposed easily because of the Kronecker delta function properties of the approaching functions. Three classical 2D elasticity problems have been examined to verify the performance of the method proposed. The results show that this method has faster convergence and higher accuracy than the conventional boundary type numerical methods.

关键词： numerical method singular integral boundary effect radial basis function networks integral equation virtual boundary Source function singular value decomposition

NOTE ON A BOUNDARY VALUE PSOBLEM OF POISSON'S EQUATION

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Applied Mathematics(A Journal of Chinese Universities) 1995年第1期10卷 35-38页

作者： FENGCHAOKENG HSULIZHI YUHONGQUAN DepaxtmentofAeronauticsEnginvering TamkangUnivrsityTaipeiTaiwan DepartmentofMathematics DalianUniversityofTechnologyDalian116023

This note shows that for a BVP of Poisson's equation with Qm(u, v) asits Source function, a direct evaluation of some integrals yields the same exact resultsas obtained by similarity analysis.

关键词： 31A25 31A30 35C05 Similarity analysis Source function direct calculus analysis