注意到simpleFoam源码的createField.H中含有一行代码：

singlePhaseTransportModel laminarTransport(U, phi);

将类singlePhaseTransportModel实例化为laminarTransport，并且传给构造函数两个参数U和phi。
在simpleFoam.C中找到了#include "singlePhaseTransportModel.H"。类singlePhaseTransportModel很有可能在里面定义，因此进入singlePhaseTransportModel.H。
其路径为$FOAM_SRC/transportModels/incompressible/singlePhaseTransportModel/singlePhaseTransportModel.H，发现类singlePhaseTransportModel，及其构造函数的声明。因此进入singlePhaseTransportModel.C中查看其定义。

Foam::singlePhaseTransportModel::singlePhaseTransportModel
(
    const volVectorField& U,
    const surfaceScalarField& phi
)
:
    IOdictionary
    (
        IOobject
        (
            "transportProperties",
            U.time().constant(),
            U.db(),
            IOobject::MUST_READ_IF_MODIFIED,
            IOobject::NO_WRITE
        )
    ),
    viscosityModelPtr_(viscosityModel::New("nu", *this, U, phi))
{}

在类singlePhaseTransportModel构造前，先建立了读取constant/transportProperties的字典，并用
viscosityModel::New返回了一个叫viscosityModelPtr_的指针。
因此需要查看viscosityModel::New的定义。路径为$FOAM_SRC/transportModels/incompressible/viscosityModels/viscosityModel/viscosityModelNew.C。相关代码如下：

Foam::autoPtr<Foam::viscosityModel> Foam::viscosityModel::New
(
    const word& name,
    const dictionary& viscosityProperties,
    const volVectorField& U,
    const surfaceScalarField& phi
)
{
    const word modelType(viscosityProperties.lookup("transportModel"));

    Info<< "Selecting incompressible transport model " << modelType << endl;

    auto cstrIter = dictionaryConstructorTablePtr_->cfind(modelType);

    if (!cstrIter.found())
    {
        FatalErrorInFunction
            << "Unknown viscosityModel type "
            << modelType << nl << nl
            << "Valid viscosityModels :" << endl
            << dictionaryConstructorTablePtr_->sortedToc()
            << exit(FatalError);
    }

    return autoPtr<viscosityModel>
        (cstrIter()(name, viscosityProperties, U, phi));
}

此函数本质是在contant/transportProperties文件中查询关键字transportModel对应的值（以Newtonian为例），并在哈希表中查看是否存在这个Newtonian。返回Newtonian在哈希表中对应的值。以我目前的学习经验来看，这个对应值应该是类Newtonian的一个临时对象，并用cstrIter()(name, viscosityProperties, U, phi)括号里的参数进行了初始化。因此需要找到类Newtonian的构造函数。路径为：$FOAM_SRC/transportModels/incompressible/viscosityModels/Newtonian/Newtonian.C

Foam::viscosityModels::Newtonian::Newtonian
(
    const word& name,
    const dictionary& viscosityProperties,
    const volVectorField& U,
    const surfaceScalarField& phi
)
:
    viscosityModel(name, viscosityProperties, U, phi),
    nu0_("nu", dimViscosity, viscosityProperties_),
    nu_
    (
        IOobject
        (
            name,
            U_.time().timeName(),
            U_.db(),
            IOobject::NO_READ,
            IOobject::NO_WRITE
        ),
        U_.mesh(),
        nu0_
    )
{}

在构造类Newtonian时先构造了类viscosityModel。注意到类viscosityModel是类Newtonian的一个父类。因此需要找到类viscosityModel的构造函数。路径为：$FOAM_SRC/transportModels/incompressible/viscosityModels/viscosityModel/viscosityModel.C

Foam::viscosityModel::viscosityModel
(
    const word& name,
    const dictionary& viscosityProperties,
    const volVectorField& U,
    const surfaceScalarField& phi
)
:
    name_(name),
    viscosityProperties_(viscosityProperties),
    U_(U),
    phi_(phi)
{}

类viscosityModel的构造函数实际是将形参用于name_，viscosityProperties_，U_和phi_初始化了。这里的viscosityProperties_由于被类Newtonian继承，在类Newtonian的构造函数中可以看见nu0_使用了viscosityProperties_进行初始化。而viscosityProperties_的本质实际就是

 IOdictionary
    (
        IOobject
        (
            "transportProperties",
            U.time().constant(),
            U.db(),
            IOobject::MUST_READ_IF_MODIFIED,
            IOobject::NO_WRITE
        )
    ),

返回看nu0_的初始化：

nu0_("nu", dimViscosity, viscosityProperties_)

实际是读取constant/transportProperties文件里的nu关键字对应的dimensionedScalar。
而nu_

    nu_
    (
        IOobject
        (
            name,
            U_.time().timeName(),
            U_.db(),
            IOobject::NO_READ,
            IOobject::NO_WRITE
        ),
        U_.mesh(),
        nu0_
    )

nu_则是以nu0_这个dimensionedScalar构建了一个volScalarField。

此贴基本完结，按着源代码琢磨了一下午，基本弄清楚了是如何计算的。nearestPoint()主要使用了实时碰撞检测算法，可以计算出网格中心点到一个面的最短距离。这个最短距离是通过寻找面上离网格中心点的最近点来计算的。等我过段时间总结好了，到时候再补充到这个贴子下面。

在头文件找到了描述：The low-Re correction is activated by setting the entry lowReCorrection to 'on'; in this mode the model switches between laminar and turbulent functions based on the laminar-to-turbulent y+ value derived from kappa and E. When the lowReCorrection is inactive, the wall function operates in high-Re mode.可能是在constant文件里使用这epsilonWallFunction的时候能够选择打不打开LowRe

@cresendo https://mp.weixin.qq.com/s/5aoUmeQGCqULXuBe73AtdA
今天出了，一个简单教程

感觉是不是fluent有什么黑科技，在fluent里能算，在of里发散了。。

似乎是网格尺寸的原因，我把速度缩小１０倍，能算了，说明以前的Ｙ+可能有问题

遇到一个奇怪的事情，在做模拟的时候，用足尺模型计算可以正常算，做缩尺模型的时候就会发散
我做的二维模拟，厚度方向只有一层网格，边界条件按论文设置的，论文用fluent算的缩尺模型，我放大到足尺模型算没有问题，但是按论文的尺寸算，第一步Uz就是solution singularity，算着算着epsilon就发散了，很奇怪。我用的simpleFoam，大家有啥建议吗，按理说应该能算啊。。。

RAS
{
    RASModel        realizableKE;
    turbulence      on;
    printCoeffs     on;
    A0              4;
    C2              1.9;
    sigmak          1;
    sigmaEps        1.2;
}

No MRF models present

No finite volume options present

Starting time loop

wallShearStress wallShearStress:
    processing all wall patches

Time = 0.01

DILUPBiCGStab:  Solving for Ux, Initial residual = 1, Final residual = 9.02931e-11, No Iterations 5
DILUPBiCGStab:  Solving for Uz:  solution singularity
GAMG:  Solving for p, Initial residual = 1, Final residual = 0.0511143, No Iterations 14
GAMG:  Solving for p, Initial residual = 9.35553e-05, Final residual = 7.3953e-06, No Iterations 2
time step continuity errors : sum local = 5.93648e-05, global = -2.24242e-05, cumulative = -2.24242e-05
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.141893, Final residual = 1.91784e-12, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 1, Final residual = 2.77584e-10, No Iterations 5
ExecutionTime = 1.25 s  ClockTime = 2 s

Time = 0.02

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.527912, Final residual = 5.42646e-12, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.587444, Final residual = 1.93572e-11, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.0040408, Final residual = 0.000253175, No Iterations 4
GAMG:  Solving for p, Initial residual = 0.00119141, Final residual = 0.000118566, No Iterations 6
time step continuity errors : sum local = 0.000903519, global = 0.000115926, cumulative = 9.35023e-05
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00632051, Final residual = 4.41338e-13, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.93484, Final residual = 9.44193e-11, No Iterations 5
ExecutionTime = 1.75 s  ClockTime = 2 s

Time = 0.03

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.296853, Final residual = 3.58872e-10, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.358972, Final residual = 3.93449e-10, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.0399261, Final residual = 0.00208552, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00341154, Final residual = 0.000273619, No Iterations 7
time step continuity errors : sum local = 0.00196847, global = 0.0002969, cumulative = 0.000390402
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.0295801, Final residual = 9.2042e-13, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.171095, Final residual = 5.49745e-10, No Iterations 5
ExecutionTime = 2.22 s  ClockTime = 3 s

Time = 0.04

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.136215, Final residual = 5.49597e-11, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.31202, Final residual = 1.31588e-10, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.130254, Final residual = 0.00470188, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00639474, Final residual = 0.000576745, No Iterations 8
time step continuity errors : sum local = 0.00159515, global = 0.000184109, cumulative = 0.000574511
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.0325781, Final residual = 7.34046e-12, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.150909, Final residual = 1.5092e-10, No Iterations 5
ExecutionTime = 2.72 s  ClockTime = 3 s

Time = 0.05

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.309871, Final residual = 7.73697e-11, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.461963, Final residual = 1.28081e-10, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.167412, Final residual = 0.00510895, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00610619, Final residual = 0.000483956, No Iterations 7
time step continuity errors : sum local = 0.00101936, global = 5.21071e-05, cumulative = 0.000626618
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00882784, Final residual = 7.51562e-13, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.236641, Final residual = 6.08151e-11, No Iterations 5
ExecutionTime = 3.2 s  ClockTime = 3 s

Time = 0.06

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.341882, Final residual = 1.0659e-10, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.454444, Final residual = 1.41636e-10, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.132903, Final residual = 0.00323376, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00381782, Final residual = 0.000236562, No Iterations 6
time step continuity errors : sum local = 0.000731669, global = -0.000105249, cumulative = 0.000521369
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.0075595, Final residual = 4.3385e-12, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.192427, Final residual = 3.91865e-10, No Iterations 5
ExecutionTime = 3.68 s  ClockTime = 4 s

Time = 0.07

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.282586, Final residual = 2.67545e-10, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.35265, Final residual = 2.45834e-10, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.151323, Final residual = 0.00331011, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00398265, Final residual = 0.000390266, No Iterations 5
time step continuity errors : sum local = 0.00105724, global = -8.7694e-05, cumulative = 0.000433675
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00759443, Final residual = 1.21657e-12, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.18612, Final residual = 3.54752e-11, No Iterations 5
ExecutionTime = 4.13 s  ClockTime = 4 s

Time = 0.08

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.213044, Final residual = 6.05622e-11, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.28304, Final residual = 9.67631e-11, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.189574, Final residual = 0.00373539, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00463947, Final residual = 0.000336507, No Iterations 7
time step continuity errors : sum local = 0.000557299, global = -5.79127e-05, cumulative = 0.000375763
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00781571, Final residual = 1.93204e-12, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.138057, Final residual = 3.95958e-11, No Iterations 5
ExecutionTime = 4.62 s  ClockTime = 5 s

Time = 0.09

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.237589, Final residual = 2.96319e-11, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.243097, Final residual = 1.46831e-10, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.180488, Final residual = 0.00312019, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00383925, Final residual = 0.00026896, No Iterations 7
time step continuity errors : sum local = 0.00035406, global = -2.62236e-05, cumulative = 0.000349539
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.006831, Final residual = 3.72725e-13, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.126435, Final residual = 2.17405e-11, No Iterations 5
ExecutionTime = 5.09 s  ClockTime = 5 s

Time = 0.1

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.35012, Final residual = 3.04751e-11, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.30704, Final residual = 8.67602e-11, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.149198, Final residual = 0.00253316, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00305357, Final residual = 0.000284755, No Iterations 5
time step continuity errors : sum local = 0.000375062, global = 2.83423e-05, cumulative = 0.000377881
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00611188, Final residual = 1.87536e-13, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.289974, Final residual = 2.50168e-11, No Iterations 5
ExecutionTime = 5.88 s  ClockTime = 6 s

wallShearStress wallShearStress write:
    writing field wallShearStress
    min/max(down) = (-2.87883 -3.63059e-22 -0.0927051), (0.461882 3.65848e-22 0.0998493)
    min/max(roof) = (-17.9474 -1.26777e-18 -3.09904), (-0.42612 1.16826e-18 6.57279)
    min/max(buildingWall) = (-6.27984 -1.34705e-19 -2.37151), (0.222287 1.01572e-19 6.15707)
Time = 0.11

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.531763, Final residual = 2.03224e-12, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.56992, Final residual = 2.11653e-12, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.153026, Final residual = 0.00256444, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00310925, Final residual = 0.000212052, No Iterations 7
time step continuity errors : sum local = 0.00026462, global = 1.89049e-05, cumulative = 0.000396786
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.0049126, Final residual = 9.09796e-14, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.282556, Final residual = 9.72273e-13, No Iterations 5
ExecutionTime = 6.4 s  ClockTime = 7 s

Time = 0.12

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.23185, Final residual = 1.68742e-11, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.377097, Final residual = 1.61394e-11, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.175782, Final residual = 0.0040422, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00486161, Final residual = 0.000340632, No Iterations 5
time step continuity errors : sum local = 0.000478204, global = 5.30041e-05, cumulative = 0.00044979
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00552237, Final residual = 1.23137e-13, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.394754, Final residual = 2.5363e-11, No Iterations 5
ExecutionTime = 6.84 s  ClockTime = 7 s

Time = 0.13

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.379743, Final residual = 1.63324e-11, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.230827, Final residual = 4.62169e-12, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.207157, Final residual = 0.00627811, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00764946, Final residual = 0.000568072, No Iterations 7
time step continuity errors : sum local = 0.000345064, global = 3.01655e-05, cumulative = 0.000479956
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00351726, Final residual = 8.00546e-14, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.386289, Final residual = 1.57371e-13, No Iterations 5
ExecutionTime = 7.33 s  ClockTime = 8 s

Time = 0.14

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.649438, Final residual = 4.46392e-16, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.506957, Final residual = 1.07223e-16, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.156169, Final residual = 0.00375195, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00165985, Final residual = 0.000160854, No Iterations 3
time step continuity errors : sum local = 0.00058144, global = 7.92418e-06, cumulative = 0.00048788
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00170993, Final residual = 2.94273e-17, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.329833, Final residual = 1.51244e-18, No Iterations 5
ExecutionTime = 7.77 s  ClockTime = 8 s

Time = 0.15

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.571959, Final residual = 3.32197e-16, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.458761, Final residual = 1.52795e-17, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.0452743, Final residual = 0.00151925, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.00267839, Final residual = 0.000230421, No Iterations 1
time step continuity errors : sum local = 0.00342145, global = -1.32423e-05, cumulative = 0.000474638
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.000546564, Final residual = 2.02553e-17, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.130893, Final residual = 2.82138e-19, No Iterations 5
ExecutionTime = 8.17 s  ClockTime = 8 s

Time = 0.16

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.463509, Final residual = 1.57563e-17, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.509736, Final residual = 4.59172e-18, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.134174, Final residual = 0.00768087, No Iterations 2
GAMG:  Solving for p, Initial residual = 0.00363852, Final residual = 0.000201176, No Iterations 4
time step continuity errors : sum local = 0.0210048, global = -0.000201257, cumulative = 0.000273381
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00400355, Final residual = 8.29593e-18, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.366453, Final residual = 1.20683e-18, No Iterations 5
ExecutionTime = 8.63 s  ClockTime = 9 s

Time = 0.17

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.267952, Final residual = 4.29013e-23, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.540221, Final residual = 5.71911e-22, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.123787, Final residual = 0.00286107, No Iterations 1
GAMG:  Solving for p, Initial residual = 6.716e-05, Final residual = 3.30864e-06, No Iterations 6
time step continuity errors : sum local = 1172.79, global = -133.626, cumulative = -133.626
DILUPBiCGStab:  Solving for epsilon, Initial residual = 0.00118844, Final residual = 9.31074e-18, No Iterations 5
DILUPBiCGStab:  Solving for k, Initial residual = 0.43358, Final residual = 1.23182e-16, No Iterations 5
ExecutionTime = 9.1 s  ClockTime = 9 s

Time = 0.18

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.699964, Final residual = 2.85242e-22, No Iterations 5
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.654102, Final residual = 3.34865e-22, No Iterations 5
GAMG:  Solving for p, Initial residual = 0.1765, Final residual = 8.0125e-05, No Iterations 1
GAMG:  Solving for p, Initial residual = 0.332435, Final residual = 0.0152816, No Iterations 1
time step continuity errors : sum local = 7.41639e+18, global = 2.63517e+13, cumulative = 2.63517e+13
DILUPBiCGStab:  Solving for epsilon, Initial residual = 2.32053e-07, Final residual = 1.76158e-19, No Iterations 5
bounding epsilon, min: -70.8119 max: 8.51758e+10 average: 6.33029e+06
DILUPBiCGStab:  Solving for k, Initial residual = 1, Final residual = 4.21351e-16, No Iterations 5
ExecutionTime = 9.51 s  ClockTime = 10 s

修改后边角处边界层也加上了：

但是在加密交界面网格很畸形：

这是什么导致的呢？有没有改进办法

找到解决办法了，在addLayersControls里把featureAngle从60改成90就行

我感觉的我模型其实不复杂，但是边界层生成的时候缺有点问题，请大家帮忙看一下如何改进比较好
下图是shm第二步snap后的图：

感觉吻合的还可以的。
然后加边界层后发现夹角处的边界层出了问题：

我shm中对边界层的控制如下：

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v1806                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      snappyHexMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

// Which of the steps to run
castellatedMesh true;
snap            true;
addLayers       true;

// Geometry. Definition of all surfaces. All surfaces are of class
// searchableSurface.
// Surfaces are used
// - to specify refinement for any mesh cell intersecting it
// - to specify refinement for any mesh cell inside/outside/near
// - to 'snap' the mesh boundary to the surface
geometry
{
    flatRoof.stl
    {
        type triSurfaceMesh;
        name roof;
    }

    refinementBox
    {
        type searchableBox;
        min (20 0 0);
        max (80   1.0 8);
    }
};



// Settings for the castellatedMesh generation.
castellatedMeshControls
{

    // Refinement parameters
    // ~~~~~~~~~~~~~~~~~~~~~

    // If local number of cells is >= maxLocalCells on any processor
    // switches from from refinement followed by balancing
    // (current method) to (weighted) balancing before refinement.
    maxLocalCells 100000;

    // Overall cell limit (approximately). Refinement will stop immediately
    // upon reaching this number so a refinement level might not complete.
    // Note that this is the number of cells before removing the part which
    // is not 'visible' from the keepPoint. The final number of cells might
    // actually be a lot less.
    maxGlobalCells 2000000;

    // The surface refinement loop might spend lots of iterations refining just a
    // few cells. This setting will cause refinement to stop if <= minimumRefine
    // are selected for refinement. Note: it will at least do one iteration
    // (unless the number of cells to refine is 0)
    minRefinementCells 10;

    // Allow a certain level of imbalance during refining
    // (since balancing is quite expensive)
    // Expressed as fraction of perfect balance (= overall number of cells /
    // nProcs). 0=balance always.
    maxLoadUnbalance 0.10;


    // Number of buffer layers between different levels.
    // 1 means normal 2:1 refinement restriction, larger means slower
    // refinement.
    nCellsBetweenLevels 3;



    // Explicit feature edge refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    // Specifies a level for any cell intersected by its edges.
    // This is a featureEdgeMesh, read from constant/triSurface for now.
    features
    (
    );



    // Surface based refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~

    // Specifies two levels for every surface. The first is the minimum level,
    // every cell intersecting a surface gets refined up to the minimum level.
    // The second level is the maximum level. Cells that 'see' multiple
    // intersections where the intersections make an
    // angle > resolveFeatureAngle get refined up to the maximum level.

    refinementSurfaces
    {
        roof
        {
            // Surface-wise min and max refinement level
            level (1 1);

            // Optional specification of patch type (default is wall). No
            // constraint types (cyclic, symmetry) etc. are allowed.
            patchInfo
            {
                type wall;
                inGroups (roof);
            }
        }
    }

    // Resolve sharp angles
    resolveFeatureAngle 30;


    // Region-wise refinement
    // ~~~~~~~~~~~~~~~~~~~~~~

    // Specifies refinement level for cells in relation to a surface. One of
    // three modes
    // - distance. 'levels' specifies per distance to the surface the
    //   wanted refinement level. The distances need to be specified in
    //   descending order.
    // - inside. 'levels' is only one entry and only the level is used. All
    //   cells inside the surface get refined up to the level. The surface
    //   needs to be closed for this to be possible.
    // - outside. Same but cells outside.

    refinementRegions
    {
        refinementBox
        {
            mode inside;
            levels ((1E15 1));
        }
    }


    // Mesh selection
    // ~~~~~~~~~~~~~~

    // After refinement patches get added for all refinementSurfaces and
    // all cells intersecting the surfaces get put into these patches. The
    // section reachable from the locationInMesh is kept.
    // NOTE: This point should never be on a face, always inside a cell, even
    // after refinement.
    locationInMesh (0.5 0.5 0.5);


    // Whether any faceZones (as specified in the refinementSurfaces)
    // are only on the boundary of corresponding cellZones or also allow
    // free-standing zone faces. Not used if there are no faceZones.
    allowFreeStandingZoneFaces true;
}



// Settings for the snapping.
snapControls
{
    //- Number of patch smoothing iterations before finding correspondence
    //  to surface
    nSmoothPatch 3;

    //- Relative distance for points to be attracted by surface feature point
    //  or edge. True distance is this factor times local
    //  maximum edge length.
    tolerance 2.0;

    //- Number of mesh displacement relaxation iterations.
    nSolveIter 30;

    //- Maximum number of snapping relaxation iterations. Should stop
    //  before upon reaching a correct mesh.
    nRelaxIter 5;

    // Feature snapping

        //- Number of feature edge snapping iterations.
        //  Leave out altogether to disable.
        nFeatureSnapIter 10;

        //- Detect (geometric only) features by sampling the surface
        //  (default=false).
        implicitFeatureSnap false;

        //- Use castellatedMeshControls::features (default = true)
        explicitFeatureSnap true;

        //- Detect points on multiple surfaces (only for explicitFeatureSnap)
        multiRegionFeatureSnap false;
}



// Settings for the layer addition.
addLayersControls
{
    // Are the thickness parameters below relative to the undistorted
    // size of the refined cell outside layer (true) or absolute sizes (false).
    relativeSizes true;

    // Per final patch (so not geometry!) the layer information
    layers
    {
        "roof"
        {
            nSurfaceLayers 2;
        }
    }

    // Expansion factor for layer mesh
    expansionRatio 1.2;

    // Wanted thickness of final added cell layer. If multiple layers
    // is the thickness of the layer furthest away from the wall.
    // Relative to undistorted size of cell outside layer.
    // See relativeSizes parameter.
    //finalLayerThickness 1.0;
    firstLayerThickness 0.5;
    // Minimum thickness of cell layer. If for any reason layer
    // cannot be above minThickness do not add layer.
    // Relative to undistorted size of cell outside layer.
    minThickness 0.3;

    // If points get not extruded do nGrow layers of connected faces that are
    // also not grown. This helps convergence of the layer addition process
    // close to features.
    // Note: changed(corrected) w.r.t 1.7.x! (didn't do anything in 1.7.x)
    nGrow 0;

    // Advanced settings

    // When not to extrude surface. 0 is flat surface, 90 is when two faces
    // are perpendicular
    featureAngle 60;

    // At non-patched sides allow mesh to slip if extrusion direction makes
    // angle larger than slipFeatureAngle.
    slipFeatureAngle 30;

    // Maximum number of snapping relaxation iterations. Should stop
    // before upon reaching a correct mesh.
    nRelaxIter 3;

    // Number of smoothing iterations of surface normals
    nSmoothSurfaceNormals 1;

    // Number of smoothing iterations of interior mesh movement direction
    nSmoothNormals 3;

    // Smooth layer thickness over surface patches
    nSmoothThickness 10;

    // Stop layer growth on highly warped cells
    maxFaceThicknessRatio 0.5;

    // Reduce layer growth where ratio thickness to medial
    // distance is large
    maxThicknessToMedialRatio 0.3;

    // Angle used to pick up medial axis points
    // Note: changed(corrected) w.r.t 1.7.x! 90 degrees corresponds to 130
    // in 1.7.x.
    minMedianAxisAngle 90;


    // Create buffer region for new layer terminations
    nBufferCellsNoExtrude 0;


    // Overall max number of layer addition iterations. The mesher will exit
    // if it reaches this number of iterations; possibly with an illegal
    // mesh.
    nLayerIter 50;
}



// Generic mesh quality settings. At any undoable phase these determine
// where to undo.
meshQualityControls
{
    #include "meshQualityDict"


    // Advanced

    //- Number of error distribution iterations
    nSmoothScale 4;
    //- Amount to scale back displacement at error points
    errorReduction 0.75;
}


// Advanced

// Write flags
writeFlags
(
    scalarLevels
    layerSets
    layerFields     // write volScalarField for layer coverage
);


// Merge tolerance. Is fraction of overall bounding box of initial mesh.
// Note: the write tolerance needs to be higher than this.
mergeTolerance 1e-6;


// ************************************************************************* //

大家有什么建议么？提高一下边界层的质量

@cresendo 就叫OpenFOAM。。七个人在做，我的是周二发

@cccrrryyy fluent里面壁面函数只用设置一下，而OF里所有湍流变量都要设置。。我都搞不明白什么时候该搭配什么。只是知道根据y+简单判断一下该用哪种。。

@cresendo 是的。主要是编译麻烦，我已经搞清楚codedFunctionObject了。用codedFunctionObject好处是不用去改源代码，可以方便得给别人用，嘿嘿。相当于加了一个外载程序，嘿嘿。下周二会在公众号里分享一下使用方法，到时候也到cfd中文网来。