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Implementation of a smoothing pressure correction approach to the pressure-correction equation in order to maintain the use of simplec algorithms on non-staggered grids

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PROGRESS IN COMPUTATIONAL FLUID DYNAMICS 2010年第1期10卷 40-50页

作者： Anany, M. N. Schnell, U. Scheffknecht, G. Univ Stuttgart Inst Proc Engn & Power Plant Technol D-70569 Stuttgart Germany

Date (1996) introduced a pressure-correction equation containing mass-conserving and smoothing pressure correction terms to solve the Navier-Stokes equations. The benefit of the smoothing terms is satisfying the stokes's relation which is often overlooked as well as overcoming the decoupling problem of the pressure-velocity fields, which renders it applicable to collocated (non-staggered) grids. His derivation relied on assumptions relevant to the SIMPLE algorithm (Caretto et al., 1972). Such assumptions are, unfortunately, not directly applicable to simplec procedures (van Doormaal and Raithby, 1984). The main purpose of this paper is to extend the pressure-correction equation proposed by Date (1996) to simplec algorithms.

关键词： colocated grid collocated grid non-staggered grid SIMPLE algorithm simplec algorithm smoothing pressure corrections

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Single-phase Computational Fluid Dynamics Applicability for the Study of Three-dimensional Flow in 5×5 Rod Bundles with Spacer Grids

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 738-744页

作者： TIAN Ruifeng MAO Xiaohui GAO Puzhen HUANG Yanping College of Nuclear Science and Technology Harbin Engineering University Harbin 150001 China National Defense Key Discipline Laboratory of Nuclear Safety and Simulation Technology Harbin Engineering University Harbin 150001 China National Key Laboratory of Bubble Physics and Nature Circulation Nuclear Power Institute of China Chengdu 610041 China

Spacer grids play an important role in pressurized water reactor（PWR） fuel assembly in that they have significant influence on the thermal-hydraulic characteristics of the reactor *** so far,the numerical studies are performed without regarding dimple and spring of spacer grids,just considering mixing ***,these studies use k-ε turbulence model without considering the suitability of the other turbulence models upon the different spacer grids flow.A study is carried out to understand the 3-D single-phase flow in AFA-2G 5×5 rod bundles with spacer grids based on numerical *** order to investigate the suitability of different turbulence models,k-ε model and k-ω model,the influence of different parts of spacer grid on the fluid flow is also *** using second-order upwind scheme,hybrid grids technique,and improved simplec algorithm,the Reynolds averaged mass conservation and momentum conservation equations are solved,and the pressure and velocity field of flow are *** numerical simulation results are compared with experiment results and the agreement is *** simulation results show the influences of the spring,dimple and mixing vane,and the different characteristics of the k-ε model and k-ω *** with the experiment results,the simulation results suggest that the k-ω model is suitable for the simulation of the rod bundle flow with spacer grids;the spring and dimple are the main causes of the pressure loss in the spacer grid *** friction coefficient of the channel with spring and dimple is 1.5 times the coefficient of the channel with the *** results are beneficial to enhance the simulation ability of spacer grids flow and optimization design ability of spaces grid.

关键词： rod bundles spacer grids turbulence model simplec algorithm

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THREE-DIMENSIONAL SIMULATION OF MEANDERING RIVER BASED ON 3-D RNG k-ε TURBULENCE MODEL

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Journal of Hydrodynamics 2008年第4期20卷 448-455页

作者： ZHANG Ming-liang SHEN Yong-ming State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024China Department of Civil and Structural Engineering The Hong Kong Polytechnic University Hong Kong China

A 3-D numerical model for calculating flow in non-curvilinear coordinates was established in this article. The flow was simulated by solving the full Reynolds-averaged Navier-Stokes equations with the RNG κ-ε turbulence model. In the horizontal x-y-plane, a boundary-fitted curvilinear co-ordinate system was adopted, while in the vertical direction, a σ co-ordinate transformation was used to represent the free surface and bed topography. The water level was determined by solving the 2-D Poisson equation derived from 2-D depth averaged momentum equations. The finite-volume method was used to discretize the equations and the simplec algorithm was applied to acquire the coupling of velocity and pressure. This model was applied to simulate the meandering channels and natural rivers, and the water levels and the velocities for all sections were given. By contrasting and analyzing, the agreement with measurements is generally good. The feasibility studies of simulating flow of the natural fiver have been conducted to demonstrate its applicability to hydraulic engineering research.

关键词： non-orthogonal curvilinear coordinates RNG κ-ε turbulence model 2-D Poisson equation simplec algorithm depth averaged equation

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Numerical model of flow and pollutant transportation in non-orthogonal curvilinear coordinates

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Journal of Environmental Sciences 2004年第2期16卷 293-296页

作者： WUXiu-guang SHENYong-ming ZHENGYong-hong YANGZhi-feng StateKeyLaboratoryofCoastalandOffshoreEngineering DalianUniversityofTechnologyDalian116024China. GuangzhouInstituteofEnergyConversion ChineseAcademyofSciencesGuangzhou510070China InstituteofEnvironmentalScience BeijingNormalUniversityBeijing100875China

The planar 2D k-ε double equations' turbulence model was adopted and transformed into non-orthogonal curvilinear coordinates. The concentration convection-diffusion was introduced to planar 2D simplec algorithm of flow in non-orthogonal curvilinear coordinates. The numerical model of pollutant transportation in non-orthogonal curvilinear coordinates was constructed. The model was applied to simulate the flow and pollutant concentration fields. In the testing concentration field, two optimal operations of contamination discharging both along bank and in the centerline at the first bend of the meandering channel were adopted. Comparison with available data showed the model developed was successful, was valuable to engineering application.

关键词： curvilinear coordinates diffusion-transportation simplec algorithm concentration fields meandering channel

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Numerical treatment of pressure Boundary Conditions in simplec

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PROGRESS IN COMPUTATIONAL FLUID DYNAMICS 2009年第3-5期9卷 269-276页

作者： Lu, Shu Shen Lee, Chang Ho Ozoe, Hiroyuki Sun Yat Sen Univ Sch Chem & Chem Engn Guangzhou 510275 Guangdong Peoples R China Korean Intellectual Property Off Precis Machinery Exam Div Machinery Met & Construct Exam Bur Taejon 302701 South Korea Kyushu Univ Inst Mat Chem & Engn Fukuoka 8168580 Japan

The purpose of this paper is to present a numerical treatment for the prediction of incompressible flow and heat transfer in domains with specified pressure boundaries, especially for simplec algorithm. This method is explained with three examples such as incompressible forced flow, buoyancy-driven flow and magneto-thermal induced air flow. These samples show the utility of this treatment with specified boundary pressures encountered in practical applications.

关键词： pressure boundary conditions simplec algorithm buoyancy-driven flow magneto-thermal convection

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Numerical modeling of gas-liquid flows in mini- and microchannels

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THERMOPHYSICS AND AEROMECHANICS 2015年第1期22卷 61-71页

作者： Guzei, D. V. Minakov, A. V. Pryazhnikov, M. I. Dekterev, A. A. Siberian Fed Univ Krasnoyarsk Russia Kutateladze Inst Thermophys SB RAS Novosibirsk Russia

The paper presents the results of testing a methodology for calculating two-phase flows in mini- and microchannels. The numerical methodology is based on the known fluid-in-cell method (VOF method) and the CSF procedure to account for surface tension forces. Solutions of several test problems of two-phase flow in microchannels, including the water-oil emulsion flow and gas-liquid flow in microchannels of the T-type and the stationary slug flow in a circular minichannel, were considered with the aid of this technique. Comparisons of numerical results with experimental data were carried out. A good agreement between the results was obtained.

关键词： two-phase flows microchannels VOF method simplec algorithm control volume method

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Depth-averaged modeling of free surface flows in open channels with emerged and submerged vegetation

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APPLIED MATHEMATICAL MODELLING 2013年第1-2期37卷 540-553页

作者： Zhang, Mingliang Li, C. W. Shen, Yongming Dalian Ocean Univ Sch Ocean & Environm Engn Dalian Peoples R China Hong Kong Polytech Univ Dept Civil & Struct Engn Kowloon Hong Kong Peoples R China Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian Peoples R China

The resistance induced by vegetation on the flow in a watercourse should be considered in projects of watercourse management and river restoration. Depth-averaged numerical model is an efficient tool to study this problem. In this study, a depth-averaged model using the finite volume method on a staggered curvilinear grid and the simplec algorithm for numerical solution is developed for simulating the hydrodynamics of free surface flows in watercourses with vegetation. For the model formulation the vegetation resistance is treated as a momentum sink and represented by a Manning type equation, and turbulence is parameterized by the k-epsilon equations. An analytical equation is derived to represent the resistance induced by submerged vegetation by an equivalent Manning roughness coefficient. Numerical simulation is carried out for the flow in an open channel with a 180 degrees bend, and the flow in a curved open channel partly covered by emerged vegetation, as well as the flow in a straight trapezoidal channel with submerged vegetation. The agreement between the computed results and the measured data is generally good, showing that the resistance due to emerged or submerged vegetation can be represented accurately by the Manning roughness equation. The computed results demonstrate that the depth-averaged modeling is a reasonable and efficient tool to study flows in watercourses with vegetations. (c) 2012 Elsevier Inc. All rights reserved.

关键词： Depth-averaged modeling Emerged and submerged vegetation Manning equation k-epsilon Turbulent model simplec algorithm

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A 3D non-linear k-ε turbulent model for prediction of flow and mass transport in channel with vegetation

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APPLIED MATHEMATICAL MODELLING 2010年第4期34卷 1021-1031页

作者： Zhang, Ming-Liang Li, C. W. Shen, Yong-Ming Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian Peoples R China Hong Kong Polytech Univ Dept Civil & Struct Engn Hong Kong Hong Kong Peoples R China

The results from a 3D non-linear k-epsilon turbulence model with vegetation are presented to investigate the flow structure, the velocity distribution and mass transport process in a straight compound open channel and a curved open channel. The 3D numerical model for calculating flow is set up in non-orthogonal curvilinear coordinates in order to calculate the complex boundary channel. The finite volume method is used to disperse the governing equations and the simplec algorithm is applied to acquire the coupling of velocity and pressure. The non-linear k-epsilon turbulent model has good useful value because of taking into account the anisotropy and not increasing the computational time. The water level of this model is determined from 2D Poisson equation derived from 2D depth-averaged momentum equations. For concentration simulation, an expression for dispersion through vegetation is derived in the present work for the mixing due to flow over vegetation. The simulated results are in good agreement with available experimental data, which indicates that the developed 3D model can predict the flow structure and mass transport in the open channel with vegetation. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Non-linear k-epsilon turbulence model simplec algorithm 2D Poisson equation Vegetation Drag force Mass transport

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DISC - An efficient method for the discretization of convection on unstructured grids

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AEROSPACE SCIENCE AND TECHNOLOGY 1997年第6期1卷 405-411页

作者： Rexroth, CH Bauer, HJ Wittig, S Lehrstuhl und Institut für Thermische Str?mungsmaschinen Universit?t Karlsruhe Kaiserstraβe 12 D-76128 Karlsruhe Germany

When using Finite Volume methods for analyzing complex flow configurations numerically, the reliability of the results largely depends on a proper modelling of the convective transport. On unstructured grids, where difficulties arise from the irregular shape of the control volumes, an accurate and stable interpolation scheme is crucial. To meet these demands, the authors have developed the Derivative based Interpolation Scheme for Convection:(DISC). The virtue of the new scheme is demonstrated in the context of a Finite Volume pressure-correction procedure on two-dimensional unstructured meshes. The flow field around a film cooled blade of a gas turbine was selected to analyze the capabilities of the approach. A comparison with experimental results reveals that the DISC interpolation attains a much better accuracy than the common Upwind scheme while hardly affecting convergence and computational effort.

关键词： FV Navier-Stokes 2D adaptive unstructured grid simplec algorithm new DISC method for convective terms calculations for film cooled turbine blade

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PERTURBATIONAL FINITE VOLUME METHOD FOR THE SOLUTION OF 2-D NAVIER-STOKES EQUATIONS ON UNSTRUCTURED AND STRUCTURED COLOCATED MESHES

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Applied Mathematics and Mechanics(English Edition) 2005年第2期26卷 242-251页

作者：高智代民果李桂波柏威 Institute of Mechanics Chinese Academy of Sciences Beijing 100080 P.R. China

Based on the first-order upwind and second-order central type of finite volume (UFV and CFV) scheme, upwind and central type of perturbation finite volume (UPFV and CPFV) schemes of the Navier-Stokes equations were developed. In PFV method, the mass fluxes of across the cell faces of the control volume (CV) were expanded into power series of the grid spacing and the coefficients of the power series were determined by means of the conservation equation itself. The UPFV and CPFV scheme respectively uses the same nodes and expressions as those of the normal first-order upwind and second-order central scheme, which is apt to programming. The results of numerical experiments about the flow in a lid-driven cavity and the problem of transport of a scalar quantity in a known velocity field show that compared to the first-order UFV and second-order CFV schemes, upwind PFV scheme is higher accuracy and resolution, especially better robustness. The numerical computation to flow in a lid-driven cavity shows that the under-relaxation factor can be arbitrarily selected ranging from (0.3) to (0.8) and convergence perform excellent with Reynolds number variation from 10~2 to 10~4.

关键词： colocated grid structured grid unstructured grid perturbation finite volume method incompressible fluid NS equations simplec algorithm Msimplec algorithm SIMPLER algorithm

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