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请教各位大佬，在OpenFOAM中计算forces时，使用的公式在哪里可以找到呢？是直接用面网格面积乘以当地压力再积分吗？扭矩是用压力乘以面积再乘以旋转半径吗？

或者如果不能导出网格连接关系的话怎么导出网格面积以及法向量呢

在OpenFOAM或者paraview中想要输出计算结果中壁面边界上的网格点坐标，网格点之间的连接关系，以及压力等变量值应该输出呢？

请教一下各位前辈，用OF算完旋转机械之后，利用paraview进行后处理，在画流线的时候发现在动网格区域显示的是相对速度的流线，怎么才能让它显示绝对速度曲线呢？

由于我的操作失误，不小心把OpenFOAM-5.0下的platForms文件夹删了，导致现在source .bashrc文件时出错，请问应该怎么补救呢？只能全部从头来过，重新安装么，还是说哪里可以找到platforms文件夹直接下载就可以。

想问一下大家OpenFOAM计算非定常时可以统计涡脱落频率吗？怎么统计呢？

如图所示，有人知道为什么吗

不好意思，图片好像没有上传成功

我在利用rhoSimpleFoam计算螺旋桨算例时，为了减少计算量，求解单通道，两边设置为cyclic边界，但不知道为什么，算出来的结果在两边cyclic上都出现了边界层，有哪位大佬知道是怎么回事吗？
/home/wbing/图片/cyclic.png

李老师，这个function可以输出Cp吗？

我是用rhoSimpleFoam计算螺旋桨，但后处理时我需要得到螺旋桨的推力，扭矩，以及螺旋桨叶片表面（或者某一截面）的叶片表面压力系数Cp，阻力系数Cf等值。我是要在controlDict里面指定什么函数吗？在网上也没找到合适的教程，求各位大神帮忙解答一下。

想要用OpenFoam计算螺旋桨或者风扇的声传播问题。所以想问一下各位在OpenFoam中有没有求解FW——H方程的求解器？

我用OpenFOAM计算外流问题，当来流速度设置为0时可以正常计算，但当来流速度大于零时最多计算一步流道就堵塞了，我怀疑是边界条件有问题。我的边界条件设置如下，请教大家这样搭配可以吗？如果不行应该是怎样呢？
U

FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    //- Set patchGroups for constraint patches
    #includeEtc "caseDicts/setConstraintTypes"

    inlet
    {
        type            fixedValue;
        value           uniform (0 0 50);
    }

    outlet
    {
        type            zeroGradient;
    }

    symm
    {
        type            slip;

    }


    propellerW-f
    {
       type            movingWallVelocity;
       value           uniform (0 0 0);
    }

    propellerW-s
    {
       type            movingWallVelocity;
       value           uniform (0 0 0);
    }

    propellerW-h
    {
       type            fixedValue;
       value           uniform (0 0 0);
    }

    propellerW-t
    {
       type            fixedValue;
       value           uniform (0 0 0);
    }
}

p

dimensions      [1 -1 -2 0 0 0 0];

internalField   uniform 101325;

boundaryField
{
    //- Set patchGroups for constraint patches
    #includeEtc "caseDicts/setConstraintTypes"

    inlet
    {
        type            zeroGradient;
    }

    outlet
    {
        type            fixedValue;
        value           uniform 101325;
    }

    symm
    {
        type            slip;

    }

    wall
    {
        type            zeroGradient;
    }
}

T

dimensions      [0 0 0 1 0 0 0];

internalField   uniform 293;

boundaryField
{
    inlet
    {
        type            fixedValue;
        value           uniform 293;
    }

    outlet     
    { 
        type            inletOutlet;
        inletValue      uniform 293;
        value           uniform 293;
    }

    symm
    {
        type            slip;

    }
    "inter.*"
    {
        type            fixedValue;
        value           $internalField;
    }
    wall
    { 
        type            zeroGradient;
    }
  

    #includeEtc "caseDicts/setConstraintTypes"
}

nuTilda

dimensions      [0 2 -1 0 0 0 0];

internalField   uniform 1e-5;
boundaryField
{
    //- Set patchGroups for constraint patches
    #includeEtc "caseDicts/setConstraintTypes"

    inlet
    {
        type            fixedValue;
        value           uniform 1e-5;
    }

    outlet
    {
        type            inletOutlet;
        inletValue      uniform 1e-5;
        value           uniform 1e-5;
    }

    symm
    {
        type            slip;

    }

    wall
    {
        type            fixedValue;
        value           uniform 0;
    }
}

nut

dimensions      [0 2 -1 0 0 0 0];

internalField   uniform 8.58e-6;

boundaryField
{
    //- Set patchGroups for constraint patches
    #includeEtc "caseDicts/setConstraintTypes"

    inlet
    {
        type            fixedValue;
        value           uniform 8.58e-6;
    }

    outlet
    {
        type            inletOutlet;
        inletValue           uniform 8.58e-06;
        value           uniform 8.58e-06;
    }

    symm
    {
        type            slip;

    }

    wall
    {
        type            nutUSpaldingWallFunction;
        value           uniform 0;
    }
}

alphat

dimensions      [1 -1 -1 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    inlet     
    {
        type    calculated;
        value   uniform 0;
    }
    outlet    
    { 
        type    calculated;
        value   uniform 0;
    }

    symm
    {
        type            slip;

    }
    "inter.*"
    {
        type            fixedValue;
        value           $internalField;
    }
    wall
    {
        type            compressible::alphatWallFunction;
        Prt             0.85;
        value           uniform 0;
    }

    #includeEtc "caseDicts/setConstraintTypes"
}

其中inlet，outlet，分别是进口和出口，几何边界条件为patch；symm为四周的自由边界，为柱状，几何边界条件为patch，propeller是计算的螺旋桨，几何边界条件为Wall；计算所用湍流模型为SA模型，所用求解器为rhoSimpleFoam,设置了两块MRF区域，MRF设置如下：

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      MRFProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

MRF1
{
    cellZone    sector_part1;
    active      yes;

    Fixed patches (propellerW-f);
    nonRotatingPatches ();

    origin    (0 0 0);
    axis      (0 0 1);
    omega     112.5737; // rad/s
}

MRF2
{
    cellZone    sector_part2;
    active      yes;

    Fixed patches (propellerW-s);
    nonRotatingPatches ();

    origin    (0 0 0);
    axis      (0 0 1);
    omega     -112.5737; // rad/s
}

在OpenFOAM中如何才能得到如下图所示的在叶片表面某一截面上的压力系数曲线呢？是在ControlDict中设置某种function还是在paraview进行后处理时生成呢？有参考的教程或者算例吗？

李老师，我用的是可变时间步长，保证CFL数小于1，所以应该不是时间步长的问题，我注意到计算是计算到某一步之后rhoEqn的最小值突然变成0了，这可能是什么原因呢？

rhoEqn max/min : 1.62584 0

同样一个算例，我在自己的电脑上运行时没有问题，当我加密网格以后（同时减少时间步长以满足CFL条件）把它挂到集群上去并行计算以后就出现了如下错误。
OpenFOAM版本是5.0，用的求解器是rhoPImpleDyMFoam,用32个核求解。有人知道是什么原因吗？

[17] #0  Foam::error::printStack(Foam::Ostream&)--------------------------------------------------------------------------
An MPI process has executed an operation involving a call to the
"fork()" system call to create a child process.  Open MPI is currently
operating in a condition that could result in memory corruption or
other system errors; your MPI job may hang, crash, or produce silent
data corruption.  The use of fork() (or system() or other calls that
create child processes) is strongly discouraged.  

The process that invoked fork was:

  Local host:          c37 (PID 390101)
  MPI_COMM_WORLD rank: 17

If you are *absolutely sure* that your application will successfully
and correctly survive a call to fork(), you may disable this warning
by setting the mpi_warn_on_fork MCA parameter to 0.
--------------------------------------------------------------------------
 at ??:?
[17] #1  Foam::sigFpe::sigHandler(int) at ??:?
[17] #2  ? in "/usr/lib64/libc.so.6"
[17] #3  Foam::divide(Foam::Field<double>&, Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
[17] #4  Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::operator/<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) at ??:?
[17] #5  Foam::CompressibleTurbulenceModel<Foam::fluidThermo>::nu() const at ??:?
[17] #6  Foam::RASModel<Foam::EddyDiffusivity<Foam::ThermalDiffusivity<Foam::CompressibleTurbulenceModel<Foam::fluidThermo> > > >::nuEff() const at ??:?
[17] #7  Foam::linearViscousStress<Foam::RASModel<Foam::EddyDiffusivity<Foam::ThermalDiffusivity<Foam::CompressibleTurbulenceModel<Foam::fluidThermo> > > > >::divDevRhoReff(Foam::GeometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh>&) const at ??:?
[17] #8  ? at ??:?
[17] #9  __libc_start_main in "/usr/lib64/libc.so.6"
[17] #10  ? at ??:?
[c37:390101] *** Process received signal ***
[c37:390101] Signal: Floating point exception (8)
[c37:390101] Signal code:  (-6)
[c37:390101] Failing at address: 0x3f90005f3d5
[c37:390101] [ 0] /usr/lib64/libc.so.6(+0x35670)[0x7f73dcd2f670]
[c37:390101] [ 1] /usr/lib64/libc.so.6(gsignal+0x37)[0x7f73dcd2f5f7]
[c37:390101] [ 2] /usr/lib64/libc.so.6(+0x35670)[0x7f73dcd2f670]
[c37:390101] [ 3] /home/wangb/OpenFOAM/OpenFOAM-5.0/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam6divideERNS_5FieldIdEERKNS_5UListIdEES6_+0x78)[0x7f73de103d48]
[c37:390101] [ 4] /home/wangb/OpenFOAM/OpenFOAM-5.0/platforms/linux64GccDPInt32Opt/lib/libturbulenceModels.so(_ZN4FoamdvINS_12fvPatchFieldENS_7volMeshEEENS_3tmpINS_14GeometricFieldIdT_T0_EEEERKS8_RKS7_+0x1cf)[0x7f73e249deef]
[c37:390101] [ 5] /home/wangb/OpenFOAM/OpenFOAM-5.0/platforms/linux64GccDPInt32Opt/lib/libcompressibleTurbulenceModels.so(_ZNK4Foam27CompressibleTurbulenceModelINS_11fluidThermoEE2nuEv+0x36)[0x7f73e20c7fa6]
[c37:390101] [ 6] /home/wangb/OpenFOAM/OpenFOAM-5.0/platforms/linux64GccDPInt32Opt/lib/libcompressibleTurbulenceModels.so(_ZNK4Foam8RASModelINS_15EddyDiffusivityINS_18ThermalDiffusivityINS_27CompressibleTurbulenceModelINS_11fluidThermoEEEEEEEE5nuEffEv+0x53)[0x7f73e20ce303]
[c37:390101] [ 7] /home/wangb/OpenFOAM/OpenFOAM-5.0/platforms/linux64GccDPInt32Opt/lib/libcompressibleTurbulenceModels.so(_ZNK4Foam19linearViscousStressINS_8RASModelINS_15EddyDiffusivityINS_18ThermalDiffusivityINS_27CompressibleTurbulenceModelINS_11fluidThermoEEEEEEEEEE13divDevRhoReffERNS_14GeometricFieldINS_6VectorIdEENS_12fvPatchFieldENS_7volMeshEEE+0x37)[0x7f73e20fd4c7]
[c37:390101] [ 8] rhoPimpleDyMFoam[0x4265a6]
[c37:390101] [ 9] /usr/lib64/libc.so.6(__libc_start_main+0xf5)[0x7f73dcd1bb15]
[c37:390101] [10] rhoPimpleDyMFoam[0x42a315]
[c37:390101] *** End of error message ***
--------------------------------------------------------------------------
mpirun noticed that process rank 17 with PID 390101 on node c37 exited on signal 8 (Floating point exception).

在求解可压缩流动时，出现了如下情况：导致最终结果发散，可能是哪个参数的问题呢？

rhoEqn max/min : 1.21419 0

如果想要设置两块旋转域（对转），dynamicMeshDict应该怎么编写呢？我像下面那样编写，结果只有sector_part2旋转。

dynamicFvMesh   dynamicMotionSolverFvMesh;

motionSolverLibs ("libfvMotionSolvers.so");

motionSolver    solidBody;

cellZone        sector_part1;

solidBodyMotionFunction  rotatingMotion;

origin      (0 0 0);
axis        (0 0 1);
omega       112.573737; // rad/s

cellZone        sector_part2;

solidBodyMotionFunction  rotatingMotion;

origin      (0 0 0);
axis        (0 0 1);
omega       -112.573737; // rad/s

正确的编写形式应该是怎样的呢？

我尝试用rhopimpleDyMFoam求解螺旋桨问题，但一运行就报错，问题可能出在哪里呢

AMI: Creating addressing and weights between 44553 source faces and 45057 target faces
AMI: Patch source sum(weights) min/max/average = 0.50648, 1.60655, 1.00129
AMI: Patch target sum(weights) min/max/average = 0.137061, 1.49198, 0.99757
AMI: Creating addressing and weights between 44565 source faces and 45078 target faces
AMI: Patch source sum(weights) min/max/average = 0, 1.51601, 1.00106
AMI: Patch target sum(weights) min/max/average = 0.0834896, 1.48141, 0.997232
#0  Foam::error::printStack(Foam::Ostream&) at ??:?
#1  Foam::sigFpe::sigHandler(int) at ??:?
#2  ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3  Foam::hePsiThermo<Foam::psiThermo, Foam::pureMixture<Foam::sutherlandTransport<Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleEnthalpy> > > >::calculate() at ??:?
#4  Foam::fluidThermo::addfvMeshConstructorToTable<Foam::hePsiThermo<Foam::psiThermo, Foam::pureMixture<Foam::sutherlandTransport<Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleEnthalpy> > > > >::New(Foam::fvMesh const&, Foam::word const&) at ??:?
#5  Foam::autoPtr<Foam::fluidThermo> Foam::basicThermo::New<Foam::fluidThermo>(Foam::fvMesh const&, Foam::word const&) at ??:?
#6  Foam::fluidThermo::New(Foam::fvMesh const&, Foam::word const&) at ??:?
#7  ? in "/home/wbing/OpenFOAM/OpenFOAM-5.x/platforms/linux64GccDPInt32Opt/bin/rhoPimpleDyMFoam"
#8  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#9  ? in "/home/wbing/OpenFOAM/OpenFOAM-5.x/platforms/linux64GccDPInt32Opt/bin/rhoPimpleDyMFoam"
Floating point exception (core dumped)

就会提示上述错误