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Efficient parallel implementation of incompressible pipe flow algorithm based on simple

CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE 2016年第6期28卷 1751-1766页

作者： Zhang, Ji-Lin Yuan, Jun-Feng Wan, Jian Mao, Jie Zhu, Li-Ting Zhou, Li Jiang, Cong-Feng Di, Peng Wang, Jue Hangzhou Dianzi Univ Sch Comp Sci & Technol Hangzhou 310018 Zhejiang Peoples R China Hangzhou Dianzi Univ Sch Mech Engn Hangzhou 310018 Zhejiang Peoples R China Univ New S Wales Sch Mech Engn Sydney NSW 2052 Australia Chinese Acad Sci Comp Network Informat Ctr Supercomp Ctr Beijing Peoples R China

Parallel semi-implicit method for pressure-linked equations(simple) algorithm is used to solve the 3-D incompressible pipe flow problem. In this paper, we proposed a novel parallel simple algorithm that uses the alternate tiling technique. Firstly, a parallel simple algorithm based on domain decomposition method was established, and the implementation of domain partition and data exchange was presented. Then, we presented serial finite difference stencil algorithm based on alternate tiling. Furthermore, an iteration space parallel two-way finite difference stencil algorithm based on alternate tiling was proposed, introducing the sequence of iterative space tiles as the sequence of execution and using time skewing technique to partition the iteration space, thus to improve the data locality of algorithm. The cache misses and the cost of communication and synchronization are reduced by reordering the tiles of iteration space. Finally, the effectiveness of the two parallel simple algorithms were compared. The results showed that the parallel simple algorithm that uses the two-way finite difference stencil algorithm based on alternate tiling has good data locality, performance, and scalability in the Deepcomp7000 cluster computing environment. Copyright (C) 2013 John Wiley & Sons, Ltd.

关键词： domain decomposition incompressible pipe flow simple algorithm TDMA alternate tiling finite difference stencil

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A COMPARISON OF COARSE AND FINE-GRAIN PARALLELIZATION STRATEGIES FOR THE simple PRESSURE CORRECTION algorithm

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS 1993年第10期16卷 891-914页

作者： LEWIS, AJ BRENT, AD BHP Research Newcastle Laboratories P.O. Box 188 Wallsend NSW 2287 Australia

The primary aim of this work was to determine the simplest and most effective parallelization strategy for control-volume-based codes solving industrial problems. It has been found that for certain classes of problems, the coarse-grain functional decomposition strategy, largely ignored due to its limited scaling capability, offers the potential for significant execution speed-ups while maintaining the inherent structure of traditional serial algorithms. Functional decomposition requires only minor modification of the existing serial code to implement and, hence, code portability across both concurrent and serial computers is maintained, Fine-grain parallelization strategies at the 'DO loop' level are also easy to implement and largely preserve code portability. Both coarse-grain functional decomposition and fine-grain loop-level parallelization strategies for the simple pressure correction algorithm are demonstrated on a Silicon Graphics 4D280S eight CPU shared memory computer system for a highly coupled, transient two-dimensional simulation involving melting of a metal in the presence of thermal-buoyancy-driven laminar convection. Problems requiring the solution of a larger number of transport equations were simulated by including further scalar variables in the calculation. While resulting in slight degradation of the convergence rate, the functional decomposition strategy exhibited higher parallel efficiencies and yielded greater speed-ups relative to the original serial code. Initially, this strategy showed a significant degradation in convergence rate due to an inconsistency in the parallel solution of the pressure correction equation. After correcting for this inconsistency, the maximum speed-up for 16 dependent variables was a factor of 5.28 with eight processors, representing a parallel efficiency of 67%. Peak efficiency of 76% was achieved using five processors to solve for 10 dependent variables.

关键词： COMPUTATIONAL FLUID DYNAMICS PARALLEL COMPUTING PARALLEL PROCESSING FUNCTIONAL DECOMPOSITION simple algorithm PRESSURE CORRECTION SCHEMES

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simple Delta Voltages Space Vector PWM algorithm for Voltage Source Multilevel Inverters 2

Simple Delta Voltages Space Vector PWM Algorithm for Voltage...

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2nd International Conference on Intelligent Energy and Power Systems (IEPS)

作者： Lopatkin, N. N. Shukshin Altai State Human Pedag Univ ASHPU Phys & Informat Dept Biisk Russia

ISBN: (纸本)9781509017690

The paper deals with the voltage source multilevel inverter space vector PWM algorithm developed on the base of one of the more general algorithms for oblique-angled coordinates of two delta voltages. The symmetry of the instantaneous output voltages on the clock cycle is provided by the simple control for the performing of the preset five-segment switching sequence. The calculations being used are quite simple and fast so they can be performed even applying a cheap DSP.

关键词： voltage space vector multilevel inverter space vector PWM (SVPWM) oblique-angled coordinates delta voltages barycentric and affine coordinates on triangles integer and fractional parts of delta voltages relative values vectors switching sequance simple algorithm THD weighted THD

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Research on the simple algorithms for the Logistics Network Layout in the Mobile Network E-Commerce

Research on the Simple Algorithms for the Logistics Network ...

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International Conference on Cyber Security Intelligence and Analytics (CSIA)

作者： Ming, Fan Xian Eurasia Univ Xian 710000 Shaanxi Peoples R China

ISBN: (纸本)9783030152352;9783030152345

The e-commerce is the dominant strategy of the digital business management, which has the characteristics of guidance, innovation and sociality. Based on this, by exploring the relationship between the e-commerce and the modern logistics distribution and service activities, and combining the analysis of its status, roles, and impact, we can give full play to the advantages of the intelligent management and promote the purpose of the social and economic cycle development. In the layout activities of the e-commerce, the rational use of the simple layout algorithm is not only conducive to the improvement and development of the e-commerce system, but is also an important factor for the development of the e-commerce.

关键词： Mobile network E-commerce Logistics network layout simple algorithm

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SIMULATION OF SEDIMENT-LADEN FLOW BY DEPTH-AVERAGED MODEL BASED ON UNSTRUCTURED COLLOCATED GRID

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Journal of Hydrodynamics 2007年第4期19卷 525-532页

作者： LIU Shi-he LUO Qiu-shi MEI Jun-ya School of Water Resource and Hydropower Wuhan University Wuhan 430072 China

The 2-D depth-averaged mathematical model for sediment-laden flows has been widely used in river control and other related engineering problems, and now it is usually solved on structured grids. Since the natural river is usually very complicated in plane boundary, and unstructured grids are more attractive in solving the problems with complicated domains, the following questions about solving 2-D depth-averaged model were discussed in this article：（1） a modified Bowyer algorithm was suggested to generate unstructured grids for natural rivers, （2） the Finite Volume Method （FVM） is employed to discretize the governing equations of the 2-D depth-averaged model and an implicit scheme was suggested with unstructured collocated grids, （3） the observed hydrological data of the Chenglingji Reach in the Yangtze River are used for verification of the presented method It seems that the suggested numerical scheme works very well, and the simulation results of both hydraulic characteristics and river bed deformation are in good agreement with the observed ones.

关键词： Bowyer algorithm unstructured grid simple algorithm

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Numerical simulation of the internal wave propagation in continuously densitystratified ocean

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Journal of Hydrodynamics 2014年第5期26卷 770-779页

作者：张洪生贾海青辜俊波李朋辉 College of Ocean Science and Engineering Shanghai Maritime University East China Electric Power Design Institute China Power Engineering Consulting Group

A numerical model is proposed to simulate the internal wave propagation in a continuously density-stratified ocean, and in the model, the momentum equations are derived from the Euler equations on the basis of the Boussinesq approximation. The governing equations, including the continuity equation and the momentum equations, are discretized with the finite volume method. The advection terms are treated with the total variation diminishing （TVD） scheme, and the simple algorithm is employed to solve the discretized governing equations. After the modeling test, the suitable TVD scheme is selected. The simple algorithm is modified to simplify the calculation process, and it is easily made to adapt to the TVD scheme. The Sommerfeld＇s radiation condition combined with a sponge layer is adopted at the outflow boundary. In the water flume with a constant water depth, the numerical results are compared to the analytical solutions with a good agreement. The numerical simulations are carried out for a wave flume with a submerged dike, and the model results are analyzed in detail. The results show that the present numerical model can effectively simulate the propagation of the internal wave.

关键词： internal wave continuously density-stratified fluid finite volume method simple algorithm numerical simulation

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NUMERICAL SIMULATION OF 2D HORIZONTAL COOLING WATER DISCHARGE IN GENERALIZED CURVILINEAR COORDINATE

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Journal of Hydrodynamics 2006年第1期18卷 91-96页

作者： XIE Zuo-tao ZHANG Xiao-feng TAN Guang-ming YANG Fang-li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072 China

2D horizontal model is one of the major mathematical methods for the research on cooling water discharge from the power plant. In this paper, the shallow water equations are transformed under the generalized curvilinear coordinate system and the elliptic differential equations are used to generate curvilinear grids, so a model in generalized curviline ar coordinate is presented to simulate 2D horizontal cooling water, Governing equations of the model are discretized by finite volume method, and non-staggered grids and simple algorithm are introduced to simplify the program during the discretization. This model is used to simulate the movement of cooling water in a simplified meandering channel and a natural channel, calculating results indicate this model can correctly reflect the movement rules of cooling water, which verifies the model can be applied in engineering practice.

关键词： cooling water generalized curvilinear coordinate non-staggered grids numerical simulation simple algorithm

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A LEVEL SET METHOD FOR SIMULATION OF RISING BUBBLE

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Journal of Hydrodynamics 2004年第4期16卷 379-385页

作者： HUANGJun-tao ZHANGHui-sheng DepartmentofMechanicsandEngineeringSciences FudanUniversityShanghai200433China

A level set method, the TVD scheme of second-order upwind procedure coupledwith flux-limiter, and simple algorithm were incorporated to simulate the flow and interfacialmotion of immiscible two-fluids with large density ratio and viscosity ratios, large topologydistortion and surface tension. As a numerical example axi-symmetric rising bubbles wereinvestigated. It is found that the method is numerically stable and has good convergence propertyand the results are in good agreement with other works.

关键词： level set method high-resolution scheme simple algorithm rising bubble

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MIXED CONVECTIVE SLIP FLOWS IN A VERTICAL PARALLEL PLATE MICROCHANNEL WITH SYMMETRIC AND ASYMMETRIC WALL HEAT FLUXES

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TRANSACTIONS OF THE CANADIAN SOCIETY FOR MECHANICAL ENGINEERING 2012年第3期36卷 207-218页

作者： Niazmand, Hamid Rahimi, Behnam Ferdowsi Univ Mashhad Dept Mech Engn Mashhad Iran

Mixed convective gaseous slip flows in an open-ended vertical parallel-plate channel with symmetric and asymmetric wall heat fluxes are numerically investigated. Buoyancy effects on developing and fully developed solutions are studied using the simple algorithm. The velocity and temperature fields are examined for different values of Knudsen number, mixed convection parameter and heat flux ratio. It is found that increasing Gr/Re leads to an increase in the heat transfer rate and friction coefficient. Also, rarefaction effects decrease the heat transfer rate and friction coefficient. The friction coefficient decreases with an increase in heat flux ratio.

关键词： mixed convection rarefaction effects microchannel simple algorithm

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Finite volume multigrid method of the planar contraction flow of a viscoelastic fluid

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS 2001年第8期36卷 885-902页

作者： Al Moatssime, H Esselaoui, D Hakim, A Raghay, S Univ Cadi Ayyad Fac Sci & Tech Dept Maths Info Marrakech Morocco Univ Ibn Tofail Lab Sci Ingenieur Anal Numer & Optimisat Kenitra Morocco

This paper reports on a numerical algorithm for the steady flow of viscoelastic fluid. The conservative and constitutive equations are solved using the finite volume method (FVM) with a hybrid scheme for the velocities and first-order upwind approximation for the viscoelastic stress. A non-uniform staggered grid system is used. The iterative simple algorithm is employed to relax the coupled momentum and continuity equations. The non-linear algebraic equations over the flow domain are solved iteratively by the symmetrical coupled Gauss-Seidel (SCGS) method. In both, the full approximation storage (FAS) multigrid algorithm is used. An Oldroyd-B fluid model was selected for the calculation. Results are reported for planar 4:1 abrupt contraction at various Weissenberg numbers. The solutions are found to be stable and smooth. The solutions show that at high Weissenberg number the domain must be long enough. The convergence of the method has been verified with grid refinement. All the calculations have been performed on a PC equipped with a Pentium III processor at 550 MHz. Copyright (C) 2001 John Wiley & Sons, Ltd.

关键词： FAS multigrid algorithm FVM non-uniform staggered grid Oldroyd-B fluid simple algorithm

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