关于nOuterCorrectors影响计算速度和计算精度的问题
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@李东岳 比如这个时间步里，PIMPLE迭代了3次，分别有三个旋转中心，如果一个时间步就取一个值，是不是迭代最后一次的旋转中心较好？
Courant Number mean: 0.00758176 max: 1.02562 Interface Courant Number mean: 8.04602e-05 max: 0.732939 Time = 8.89 PIMPLE: Iteration 1 forces forces: Not including porosity effects Rigid-body motion of the hull Centre of rotation: (3 0 0.189302) Orientation: (0.999758 0 -0.0219868 0 1 0 0.0219868 0 0.999758) Linear velocity: (0 0 -0.0427599) Angular velocity: (0 -0.0134282 0) GAMG: Solving for pcorr, Initial residual = 1, Final residual = 0.000933377, No Iterations 20 time step continuity errors : sum local = 1.87363e-10, global = 7.57308e-13, cumulative = -3.15194e-09 smoothSolver: Solving for alpha.water, Initial residual = 2.27988e-05, Final residual = 6.44668e-12, No Iterations 3 Phase-1 volume fraction = 0.803336 Min(alpha.water) = -3.41348e-13 Max(alpha.water) = 1 Applying the previous iteration compression flux MULES: Correcting alpha.water MULES: Correcting alpha.water MULES: Correcting alpha.water MULES: Correcting alpha.water Phase-1 volume fraction = 0.803336 Min(alpha.water) = -9.55996e-09 Max(alpha.water) = 1 GAMG: Solving for p_rgh, Initial residual = 0.00721682, Final residual = 4.55154e-08, No Iterations 17 time step continuity errors : sum local = 1.0765e-09, global = -2.39228e-12, cumulative = -3.15433e-09 PIMPLE: Iteration 2 forces forces: Not including porosity effects Rigid-body motion of the hull Centre of rotation: (3 0 0.189302) Orientation: (0.999758 0 -0.0219868 0 1 0 0.0219868 0 0.999758) Linear velocity: (0 0 -0.0427459) Angular velocity: (0 -0.0134156 0) GAMG: Solving for pcorr, Initial residual = 1, Final residual = 0.000949765, No Iterations 19 time step continuity errors : sum local = 1.34488e-10, global = -1.2392e-13, cumulative = -3.15445e-09 smoothSolver: Solving for alpha.water, Initial residual = 1.58142e-05, Final residual = 6.39378e-12, No Iterations 3 Phase-1 volume fraction = 0.803336 Min(alpha.water) = -3.4121e-13 Max(alpha.water) = 1 Applying the previous iteration compression flux MULES: Correcting alpha.water MULES: Correcting alpha.water MULES: Correcting alpha.water MULES: Correcting alpha.water Phase-1 volume fraction = 0.803336 Min(alpha.water) = -8.31726e-10 Max(alpha.water) = 1 GAMG: Solving for p_rgh, Initial residual = 0.000213947, Final residual = 4.56853e-08, No Iterations 19 time step continuity errors : sum local = 1.07998e-09, global = -2.92566e-12, cumulative = -3.15738e-09 PIMPLE: Iteration 3 forces forces: Not including porosity effects Rigid-body motion of the hull Centre of rotation: (3 0 0.189302) Orientation: (0.999758 0 -0.0219868 0 1 0 0.0219868 0 0.999758) Linear velocity: (0 0 -0.0427505) Angular velocity: (0 -0.0134234 0) GAMG: Solving for pcorr, Initial residual = 1, Final residual = 0.000923356, No Iterations 22 time step continuity errors : sum local = 1.36977e-10, global = -1.34327e-13, cumulative = -3.15751e-09 smoothSolver: Solving for alpha.water, Initial residual = 1.57985e-05, Final residual = 6.20267e-12, No Iterations 3 Phase-1 volume fraction = 0.803336 Min(alpha.water) = -3.412e-13 Max(alpha.water) = 1 Applying the previous iteration compression flux MULES: Correcting alpha.water MULES: Correcting alpha.water MULES: Correcting alpha.water MULES: Correcting alpha.water Phase-1 volume fraction = 0.803336 Min(alpha.water) = -5.01932e-08 Max(alpha.water) = 1 GAMG: Solving for p_rgh, Initial residual = 0.000101498, Final residual = 4.62009e-08, No Iterations 19 time step continuity errors : sum local = 1.09272e-09, global = 4.09503e-12, cumulative = -3.15342e-09 smoothSolver: Solving for omega, Initial residual =2.53013e-05, Final residual = 7.65699e-09, No Iterations 2 smoothSolver: Solving for k, Initial residual = 5.87558e-05, Final residual = 2.49652e-08, No Iterations 3 ExecutionTime = 27536.4 s ClockTime = 27737 s -
@李东岳 李老师，借楼问一下：滑移网格计算，每三个时间步会出现pcorr iteration 1000，可能出现的原因在哪方面？网格checkMesh无问题，可能会是GAMGPCG这些格式吗？
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@luofq-sysu 对，你换一下PCG，很有可能会改善
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@李东岳 谢谢李老师。1. solver.pcorr改成PCG，虽然还是出现iteration 1000，但确实快了很多。2.尝试将pcorr的tolerance从 1e-06改成1e-05，还是会出现 iteration 1000。这个有没有可能跟网格有关呢？整体计算速度慢的原因还有P_rgh也挺费事的
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fvSolution中修改每一项的tolerance，我的case是bubbleColumnEvaporatingReacting，自带的tolerance是1e-20，我修改为1e-10后计算的非常快，而且计算结果几乎相同。
FoamFile { version 2.0; format ascii; class dictionary; location "system"; object fvSolution; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // solvers { "alpha.*" { nAlphaCorr 1; nAlphaSubCycles 3; } p_rgh { solver GAMG; smoother DIC; tolerance 1e-10; relTol 0.001; } p_rghFinal { $p_rgh; relTol 0; } "U.*" { solver smoothSolver; smoother symGaussSeidel; tolerance 1e-10; relTol 0; minIter 1; } "(e|h).*" { solver smoothSolver; smoother symGaussSeidel; tolerance 1e-10; relTol 0; minIter 1; } "(k|epsilon|Theta).*" { solver smoothSolver; smoother symGaussSeidel; tolerance 1e-10; relTol 0; minIter 1; } Yi { solver smoothSolver; smoother symGaussSeidel; tolerance 1e-10; relTol 0; minIter 1; residualAlpha 1e-8; } } PIMPLE { nOuterCorrectors 1; nCorrectors 1; nNonOrthogonalCorrectors 0; } relaxationFactors { equations { ".*" 0.3; } } // ************************************************************************* //
