@向晚正愁余 感谢您的宝贵意见

@东岳 Thanks!

@东岳 好的谢谢东岳，我先用一阶迎风格式试试

@bestucan 嗯，你说的没错，我是用ssh远程连接的，我感觉我这个问题可能出现在那天学校的网络不太好的问题，我重新挂载，在机房本机操作没有问题，然后网络变好之后，远程用到现在也没问题。:mihu:

@izumi 谢谢:chitang:

@youv 好的，我会去看看书上的内容，谢谢您的指点！

@东岳
哇，前辈好~~~

这个我验证过。这个diameter是单个particle的粒径。。不是parcel的

@东岳 我对这个期刊也不熟。只是在CFDOnline上看到了这个solver。拿来用一下，结果老是发散。

Time = 0.0001 MULES: Solving for alpha1 Liquid phase volume fraction = 0.999782 Min(alpha1) = 0 Max(alpha1) = 1 GAMG: Solving for p_rgh, Initial residual = 1, Final residual = 9.17326e-07, No Iterations 32 GAMG: Solving for p_rgh, Initial residual = 4.56128e-07, Final residual = 4.56128e-07, No Iterations 0 time step continuity errors : sum local = 1.15564e-10, global = 4.67937e-12, cumulative = 4.67937e-12 GAMG: Solving for p_rgh, Initial residual = 0.000258322, Final residual = 7.79975e-07, No Iterations 4 GAMG: Solving for p_rgh, Initial residual = 7.79882e-07, Final residual = 7.79882e-07, No Iterations 0 time step continuity errors : sum local = 1.96234e-10, global = 4.41825e-12, cumulative = 9.09762e-12 GAMG: Solving for p_rgh, Initial residual = 3.261e-06, Final residual = 6.33275e-07, No Iterations 1 GAMGPCG: Solving for p_rgh, Initial residual = 6.33275e-07, Final residual = 9.32048e-09, No Iterations 5 time step continuity errors : sum local = 3.247e-11, global = -1.80463e-12, cumulative = 7.29299e-12 **** ****Pressure range: 313.455 Pa ****Max velocity: 0.168515 m/s ****Phase change energy: 0 W ****Volume change: 0 m^3/s DILUPBiCG: Solving for H, Initial residual = 0.00100367, Final residual = 7.26908e-09, No Iterations 9 DILUPBiCG: Solving for H, Initial residual = 0.000932397, Final residual = 7.34408e-09, No Iterations 9 DILUPBiCG: Solving for H, Initial residual = 0.000911756, Final residual = 7.5305e-09, No Iterations 9 ExecutionTime = 15.77 s ClockTime = 17 s Courant Number mean: 2.65292e-05 max: 0.283422 Interface Courant Number mean: 0 max: 0 Fourier number mean: 0.00271598 max: 1.81326 Time = 0.0002 MULES: Solving for alpha1 Liquid phase volume fraction = 0.999782 Min(alpha1) = -1.24343e-09 Max(alpha1) = 1 GAMG: Solving for p_rgh, Initial residual = 0.158707, Final residual = 9.59991e-07, No Iterations 33 GAMG: Solving for p_rgh, Initial residual = 9.90688e-07, Final residual = 9.90688e-07, No Iterations 0 time step continuity errors : sum local = 2.63908e-08, global = -1.91596e-08, cumulative = -1.91524e-08 GAMG: Solving for p_rgh, Initial residual = 0.00214601, Final residual = 9.69321e-07, No Iterations 12 GAMG: Solving for p_rgh, Initial residual = 9.70692e-07, Final residual = 9.70692e-07, No Iterations 0 time step continuity errors : sum local = 2.63875e-08, global = -1.9196e-08, cumulative = -3.83484e-08 GAMG: Solving for p_rgh, Initial residual = 0.000147321, Final residual = 6.99269e-07, No Iterations 4 GAMGPCG: Solving for p_rgh, Initial residual = 6.99262e-07, Final residual = 4.28891e-09, No Iterations 6 time step continuity errors : sum local = 2.62568e-08, global = -1.91768e-08, cumulative = -5.75252e-08 **** ****Pressure range: 314.046 Pa ****Max velocity: 0.158209 m/s ****Phase change energy: -0.0533324 W ****Volume change: -4.60434e-10 m^3/s DILUPBiCG: Solving for H, Initial residual = 0.0112104, Final residual = 7.17193e-09, No Iterations 11 DILUPBiCG: Solving for H, Initial residual = 0.0204525, Final residual = 6.41804e-09, No Iterations 11 DILUPBiCG: Solving for H, Initial residual = 0.0172126, Final residual = 4.83197e-09, No Iterations 11 ExecutionTime = 30.71 s ClockTime = 32 s Courant Number mean: 3.50588e-05 max: 0.283714 Interface Courant Number mean: 1.07527e-05 max: 0.225319 Fourier number mean: 0.00259948 max: 1.81296 Time = 0.0003 MULES: Solving for alpha1 Liquid phase volume fraction = 0.999788 Min(alpha1) = -4.86607e-10 Max(alpha1) = 1 GAMG: Solving for p_rgh, Initial residual = 0.248811, Final residual = 8.889e-07, No Iterations 56 GAMG: Solving for p_rgh, Initial residual = 4.8953e-08, Final residual = 4.8953e-08, No Iterations 0 time step continuity errors : sum local = 7.55439e-06, global = -5.52413e-06, cumulative = -5.58166e-06 GAMG: Solving for p_rgh, Initial residual = 0.000592748, Final residual = 8.74594e-07, No Iterations 21 GAMG: Solving for p_rgh, Initial residual = 8.86839e-07, Final residual = 8.86839e-07, No Iterations 0 time step continuity errors : sum local = 7.55687e-06, global = -5.52428e-06, cumulative = -1.11059e-05 GAMG: Solving for p_rgh, Initial residual = 2.6548e-05, Final residual = 6.06255e-07, No Iterations 2 GAMGPCG: Solving for p_rgh, Initial residual = 6.06256e-07, Final residual = 9.35864e-09, No Iterations 5 time step continuity errors : sum local = 7.55429e-06, global = -5.52414e-06, cumulative = -1.66301e-05 **** ****Pressure range: 488.866 Pa ****Max velocity: 0.275259 m/s ****Phase change energy: -15.3631 W ****Volume change: -1.32635e-07 m^3/s DILUPBiCG: Solving for H, Initial residual = 0.048899, Final residual = 9.83152e-09, No Iterations 11 DILUPBiCG: Solving for H, Initial residual = 0.0988781, Final residual = 9.59266e-09, No Iterations 11 DILUPBiCG: Solving for H, Initial residual = 0.0302533, Final residual = 4.60914e-09, No Iterations 11 ExecutionTime = 49.86 s ClockTime = 51 s Courant Number mean: 0.00111238 max: 0.451657 Interface Courant Number mean: 2.23494e-05 max: 0.451657 Fourier number mean: 0.00249786 max: 1.81736 Time = 0.0004 MULES: Solving for alpha1 Liquid phase volume fraction = 0.999796 Min(alpha1) = -0.0745499 Max(alpha1) = 1.0008 GAMG: Solving for p_rgh, Initial residual = 0.0207549, Final residual = 9.63291e-07, No Iterations 41 GAMG: Solving for p_rgh, Initial residual = 3.93396e-06, Final residual = 8.35811e-07, No Iterations 8 time step continuity errors : sum local = 9.83598e-06, global = -6.79663e-06, cumulative = -2.34267e-05 GAMG: Solving for p_rgh, Initial residual = 0.00157222, Final residual = 8.93124e-07, No Iterations 24 GAMG: Solving for p_rgh, Initial residual = 9.05354e-07, Final residual = 9.05354e-07, No Iterations 0 time step continuity errors : sum local = 9.83602e-06, global = -6.79665e-06, cumulative = -3.02234e-05 GAMG: Solving for p_rgh, Initial residual = 0.000103908, Final residual = 5.83835e-07, No Iterations 3 GAMGPCG: Solving for p_rgh, Initial residual = 5.83854e-07, Final residual = 7.0116e-09, No Iterations 5 time step continuity errors : sum local = 9.83541e-06, global = -6.79658e-06, cumulative = -3.70199e-05 **** ****Pressure range: 350.415 Pa ****Max velocity: 0.218803 m/s ****Phase change energy: -18.9019 W ****Volume change: -1.63186e-07 m^3/s DILUPBiCG: Solving for H, Initial residual = 0.1639, Final residual = 9.47499e-09, No Iterations 12 DILUPBiCG: Solving for H, Initial residual = 0.272875, Final residual = 5.27952e-09, No Iterations 12 DILUPBiCG: Solving for H, Initial residual = 0.214969, Final residual = 6.45167e-09, No Iterations 12 ExecutionTime = 68.7 s ClockTime = 70 s Courant Number mean: 0.00134918 max: 0.480577 Interface Courant Number mean: 3.19172e-05 max: 0.404985 Fourier number mean: 0.00247607 max: 1.8178 Time = 0.0005 MULES: Solving for alpha1 Liquid phase volume fraction = 0.999804 Min(alpha1) = -0.251971 Max(alpha1) = 1.04115 [4] #0 Foam::error::printStack(Foam::Ostream&) at ??:? [4] #1 Foam::sigFpe::sigHandler(int) at ??:? [4] #2 in "/lib64/libc.so.6" [4] #3 Foam::GAMGSolver::scale(Foam::Field<double>&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, Foam::Field<double> const&, unsigned char) const at ??:? [4] #4 Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMatrix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const at ??:? [4] #5 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:? [4] #6 Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:? [4] #7 Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:? [4] #8 [4] at ??:? [4] #9 __libc_start_main in "/lib64/libc.so.6" [4] #10 [4] at /usr/src/packages/BUILD/glibc-2.11.3/csu/../sysdeps/x86_64/elf/start.S:116 APPLICATION TERMINATED WITH THE EXIT STRING: Floating point exception (signal 8)

在初始化场的时候，比如这种

volScalarField test ( IOobject ( ... ) mesh //如果不写边界条件类型，除了特殊的边界条件，都为calculated，如果计算，就有值。一般情况下，边界条件很重要，要谨慎 scalar(0) );

if (potentialFlow.finalNonOrthogonalIter()) { phi -= PhiEqn.flux(); }

这段我觉得倒不是因为phi被初始化了，好像上面求解的Phi方程就不是 http://dyfluid.com/potentialFoam.html 里头的方程（6），而应该是
▽(▽P)=▽(U-▽P)
也就是代码中的phi=(U-▽P)，这样子的话也能解释速度边界条件是怎么添加到Phi 方程中的了。但有一点不很明白，就是代码中好像表达的并不完全是phi=(U-▽P)的意思，所以还是有些糊涂。

另，

MRF.makeAbsolute(phi);//此处的makeAbsolute按字面意思是取绝对值，那这个对下文中重构速度场不会产生影响么？

这句话应该不是取绝对值，可能用了多重坐标系，之前有个变换，现在变回来了，但不是很确定是不是这个意思
@东岳 @张某人
上面是我的理解，如果有不对的地方还请直接指出来，一起讨论讨论

标量够不成自己的隐性方程吧？那就在你的格式里面laplacian里面设定corrected。

谢谢，李哥指导

@izumi 谢谢啦，感激不尽

双流体和多流体求解器中需要设置的各相的直径对模拟结果有什么影响

直径直接关系到各种力的计算。是计算耦合力的重要因素。并且对传质至关重要。

需要以什么样的规则设置？

直径不能任意给定，需要参考实验值严格给出。

直径大小的设定好像跟网格尺寸有关，

http://www.sciencedirect.com/science/article/pii/S1674200117300524

看这个文章，讨论了直径的限制。目前拉格朗日那面限制的更为严格。但不能反过来说直径的大小设定和网格有关，而是网格的生成应该取决于直径。

可以使用cyclicAMI边界条件

首先你需要做两套网格，可以要么用第三方网格软件来做，要么用openfoam自带的topoSet之类的来做，两个网格最重要的是，上图中的交界面要有边界。可以是wall，也可以是patch，反正后来要改。

导入到OpenFOAM之后，要把这个交界面设置为cyclicAMI，这个可以参考pimpleDyMFoam下面的propeller算例的设置过程

滑移网格是滑移和插值的过程。就不存在网格负体积了。你的运动发散是因为变形过大产生了负体积。

0_1528241930740_无标题.png

下面是在Ansys Fluent理论指南中遇到的部分描述：

The analytic scheme is very efficient. It can become inaccurate for large steps and in situations where the particles are not in hydrodynamic equilibrium with the continuous flow. The numerical schemes implicit and trapezoidal, in combination with Automated Tracking Scheme Selection, consider most of the changes in the forces acting on the particles and are chosen as default schemes. The runge-kutta scheme is recommended of nondrag force changes along a particle integration step.

还需要进一步研究。有人见过相关文献么

@肖恩曼
那可能就需要用循环一个个赋值了

请问您用的是哪个求解器对应的算例呢？风机的转速是随入口风速变化吗？

@linhan-ge 嗯嗯好的，谢谢您的回复！