热流科学与工程亚步文源大堂E教育部重点实验室2.1.4 Comparison between Practices A and B(a)Boundary nodes have different CV.Practice A wPractice BPBoundary point has half CV.Boundary point has zero CV.(适用)(b)PracticeBismorefeasiblefor non-uniformgrid layout.-Practice APractice BCFD-NHT-EHTG11/46CENTER
11/46 Boundary point has half CV. Boundary point has zero CV. (b) Practice B is more feasible(适用) for non-uniform grid layout. Practice A Practice B Practice A 2.1.4 Comparison between Practices A and B (a) Boundary nodes have different CV. Practice B
热流科学与工程西步文通大堂E教育部重点实验室(c) For non-uniform grid layout, Practice A canguarantee the discretization accuracy of interfacederivatives(界面导数)(bxo7WEWEweweInterfaceinmiddleInterfaceisbiased(偏置)ad-de-dp(8x)e(8x)CLowerthan 2nd orderaccuracy2nd-order accuracyCFD-NHT-EHTΦ12/46CENTER
12/46 (c) For non-uniform grid layout, Practice A can guarantee the discretization accuracy of interface derivatives (界面导数). ( ) ( ) E P e e x x ( ) ( ) E P e e x x 2 nd -order accuracy Lower than 2 nd order accuracy Interface in middle Interface is biased(偏置)
热流科学与工程西步文源大堂教育部重点实验室2.1.5Grid-independent solutionsGrid generation is an iterative procedure (迭代过程);Debugging(调试)and comparison areoftenneeded.For a complicated geometry grid generationmay takeamajorpart oftotal computationaltimeGrid generation techniques has been developed asa sub-field of numerical methods.The appropriate grid fineness(细密程度)is suchthat the numerical solutions are nearly independent onthe grid numbers. Such numerical solutions are calledgrid-independent solutions (网格独立解).They arerequired for publication of a paper.CFD-NHT-EHT中13/46CENTER
13/46 2.1.5 Grid-independent solutions Grid generation is an iterative procedure(迭代过 程); Debugging (调试)and comparison are often needed. For a complicated geometry grid generation may take a major part of total computational time. The appropriate grid fineness (细密程度) is such that the numerical solutions are nearly independent on the grid numbers. Such numerical solutions are called grid-independent solutions (网格独立解). They are required for publication of a paper. Grid generation techniques has been developed as a sub-field of numerical methods
热流科学与工程步文通大学E教育部重点实验室20.00ToUoInt. Journal HeatTwGrid system used in computation&FluidFlow,199315.00(82×37)N14(3):246-25310.0040006000800010000120001400002000Grid number50中L022×1560×50Int. Journal70×60o42×2840NumericalMethodsinD50×40·75×65ONgrid system used inFluids, 1998, 28:30computation1371-1387DAa20L1301245Grid number X 10-3CFD-NHT-EHTG14/46CENTER
14/46 Int. Journal Numerical Methods in Fluids, 1998, 28: 1371-1387 Int. Journal Heat & Fluid Flow, 1993, 14(3):246-253
热流科学与工程西步文通大堂E教育部重点实验室2578X12X1024142X12X102322V21142×22×1020142Y32X2019International Journal of020000400006000080000100000Heat Mass Transfer,Gridsnumber2007,50:1163-1175CFD-NHT-EHTG15/46CENTER
15/46 Fp 0 20000 40000 60000 80000 100000 19 20 21 22 23 24 25 142×32×20 142×22×10 142×12×10 Nu Grids number 78×12×10 International Journal of Heat Mass Transfer, 2007, 50:1163 -1175