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 APracticeB11/44
11/44 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
(c)For non-uniform grid layout, Practice A can guarantee保证)thediscretizationaccuracyofinterfacederivatives（界面导数）SzEREwewEInterface in middleInterfaceisbiased（偏置）dd-0de-dp(8x)e(8x)2Lowerthan2ndorderaccuracy2nd-order accuracy12/44
12/44 (c) For non-uniform grid layout, Practice A can guarantee (保证) 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）
2.1.5Grid-independent solutionsGrid generation is an iterative procedure （迭代过程）；Debugging（调试）and comparison are oftenneeded.For a complicated geometry grid generationmay take amajorpart of total computational timeGrid 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.13/44
13/44 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
20.00ToUoInt. Journal HeatTwGrid systemused in computation&FluidFlow,199315.00(82×37)N14(3):246-25310.0040006000800010000120001400002000Grid number50中L022×1560×50Int. Journal70×60o42×2840NumericalMethodsinD50×40·75×65"nNgrid system used inFluids, 1998, 28:30computation1371-1387A.20L301245Grid number X 10-314/44
14/44 Int. Journal Numerical Methods in Fluids, 1998, 28: 1371-1387 Int. Journal Heat & Fluid Flow, 1993, 14(3):246-253
2578X12X1024142×12×102322N21142×22×1020142Y32X2019International Journal of020000400006000080000100000Heat MassTransferGridsnumber2007,50:1163-117515/44
15/44 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