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CGNS API和FVM在非结构混合网格计算中的应用 总被引:1,自引:0,他引:1
用CGNS API(CFD General Notation System Application Programming Interface)作为非结构混合网格求解器的前处理和后处理,用FVM(Finite Volume Method)作为偏微分方程求解方法.在前处理过程中,用hash表法对内部网格面和边界网格面进行编号,并计算出相应的几何信息,以满足FVM求解器的需要.从FVM求解器计算出来的各种场信息可以写入原来的CGNS文件,该文件可以被许多专业商业后处理软件(如Tecplot,Fluent,CFX等)读取和进行可视化;对于求解器,用基于网格中心的FVM及SIMPLEC(Semi Implicit Methodfor Pressure Linked Equation Consistent)方法求解压力速度耦合.最后给出两个说明算例. 相似文献
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This paper presents a local mesh refinement procedure based on a discretization over internal interfaces where the averaging is performed on the coarse side. It is implemented in a multigrid environment but can optionally be used without it. The discretization for the convective terms in the velocity and the temperature equation is the QUICK scheme, while the HYBRID-UPWIND scheme is used in the turbulence equations. The turbulence model used is a two-layer k–ϵ model. We have applied this formulation on a backward-facing step at Re=800 and on a three-dimensional turbulent ventilated enclosure, where we have resolved a geometrically complex inlet consisting of 84 nozzles. In both cases the concept of local mesh refinements was found to be an efficient and accurate solution strategy. © 1997 by John Wiley & Sons, Ltd. 相似文献
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Recently, an efficient segregated algorithm for incompressible fluid flow and heat transfer problems, called inner doubly iterative efficient algorithm for linked equations (IDEAL), has been proposed by the present authors. In the algorithm there exist inner doubly iterative processes for pressure equation at each iteration level, which almost completely overcome two approximations in SIMPLE algorithm. Thus, the coupling between velocity and pressure is fully guaranteed, greatly enhancing the convergence rate and stability of solution process. However, validations have only been conducted for two‐dimensional cases. In the present paper the performance of the IDEAL algorithm for three‐dimensional incompressible fluid flow and heat transfer problems is analyzed and a systemic comparison is made between the algorithm and three other most widely used algorithms (SIMPLER, SIMPLEC and PISO). By the comparison of five application examples, it is found that the IDEAL algorithm is the most robust and the most efficient one among the four algorithms compared. For the five three‐dimensional cases studied, when each algorithm works at its own optimal under‐relaxation factor, the IDEAL algorithm can reduce the computation time by 12.9–52.7% over SIMPLER algorithm, by 45.3–73.4% over SIMPLEC algorithm and by 10.7–53.1% over PISO algorithm. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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IntroductionThefinitevolume (FV)methodusestheintegralformoftheconservationequationasitsstartingpointandcanutilizeconvenientlydiversifiedgrids(structuredandunstructuredgrids)andissuitableforverycomplexgeometry ,whicharewhyitispopularwithengineeringandhasbeenwidelyusedinagreatvarietyofcommercialsoftwareofcomputationalfluiddynamics.Relativetothefiniteelement (FE)methodandthefinitedifferential (FD)method ,thedisadvantageofFVmethodisthatitisnothigheraccuracy .FVmethodisofsecondlevelapproximatio… 相似文献
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同位非结构和结构网格摄动有限体积法(PFV)求解二维Navier-Stokes方程组 总被引:3,自引:0,他引:3
根据NS方程组的一阶迎风和二阶中心有限体积(UFV和CFV)格式,导出NS方程组迎风和中心摄动有限体积(UPFV和CPFV)格式.该格式通过把控制体界面质量通量摄动展开成网格间距的幂级数,并由守恒方程本身求得幂级数系数而获得.迎风和中心摄动有限体积格式使用了与一阶迎风和二阶中心格式相同的基点数和相同的表达形式,宜于计算机编程.顶盖驱动方腔流和驻点流标量输运的数值实验证明,迎风PFV格式比一阶UFV、二阶CFV格式有更高的精度,更高的分辨率.尤其是良好的鲁棒特性.对顶盖驱动方腔流,在Re数从102到104范围内,亚松弛系数可在0.3~0.8任取,收敛性能良好. 相似文献
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The results from a 3D non-linear k–ε 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–ε 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. 相似文献
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A modified SIMPLEC method which can solve compressible flows at low Mach number is introduced and used to study thermoacoustic waves induced by a rapid change of temperature at a solid wall and alternatingdirection flows generated by thermoacoustic effects in a tapered resonator.The results indicate that the algorithm adopted in this paper can be used for calculating compressible flows and thermoacoustic waves.It is found that the pressure and velocity in the resonator behave as standing waves,and the tapered resonator can suppress highfrequency harmonic waves as observed in a cylindrical resonator. 相似文献
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The mathematical models of gas–liquid two-phase flow are introduced, in which the multi-mode eXtended Pom–Pom (XPP) model is selected to predict the viscoelastic behavior of polymer melt. The gas-penetration process is simulated using Level Set/SIMPLEC methods, which can capture the moving interfaces at different time, including the gas–melt interface and the melt front. The physical features such as velocity, temperature and elasticity are described at different time. The influences of gas delay time and injection pressure on gas-penetration time and penetration length are analyzed. The numerical results show that the Level Set/SIMPLEC methods can precisely trace the two moving interfaces in gas-penetration process, the fractional coverage increases at very low Deborah numbers, while at higher Deborah numbers the fractional coverage decreases, and the penetration length is affected significantly by gas delay time and injection pressure. 相似文献