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温

@赵一铭谢谢，太感谢你了，一语中的啊

温

比如说我想设置成水的属性，密度为997.78kg/m^3，动力粘度u=9.77×10^-4kg/(ms)。我该如何设置密度呢？各位大神们，求教！

温

请问还可以设置哪些流体物理属性呢？

温

我现在明白nu指的是运动粘度了。单位是m^2/s

温

我的transportProperties文件是这样的

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.1                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      transportProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //


transportModel  Newtonian;

nu              nu	 [ 0 2 -1 0 0 0 0 ] 1e-6;



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

各位大神们，我想知道nu代表了什么？还可以设置哪些流体属性？符号和单位在哪里能找到资料？谢谢~

温

这个问题现在已经解决了，是数值单位的错误。因为我的初始边界条件中入口处的p=1e-3，出口处的p=0，将网格的数值缩小了一千倍以后，使他们在同一数量级上再运行simpleFoam就不会出现“浮点数例外，核心已转储”的错误了。
我还发现在用snappyHexMesh画三维网格的时候，如果将blockMeshDict中frontAndBack设为empty，在进行snap步骤之后依然得不到很优美的平滑的网格连接。而我听从了@wwzhao 的建议之后，将frontAndBack设置成与除了出口和入口之外的其他四个面的边界条件一致，也就是patch之后，再进行snappyHexMesh，就能得到平滑的网格了。
这三天我失败了上百次，终于在昨天晚上凌晨的时候解决了这个问题，谢谢各位大神的指导，谢谢你们。

温

@wwzhao 我改了边界条件之后重生成了网格，果然模拟出来了。太谢谢您了，解决了困扰我的问题

温

@wwzhao 好的，谢谢您

温

@cfd-china 是的，用的snappyHexMesh做的网格。老师跟我说网格数多一点模拟的值更准确，我就用的100×100×100网格做的。我是照着一个案例自己取的值，案例做的是2维模拟，网格数400×100×1。我取的是一个立方体，之前模拟的都是2维，第一次做3维就懵了

温

@赵一铭之前的模拟一直用的层流，没出过这种问题。是哪个参数大小需要修改么？

温

Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
    points:           972441
    faces:            2653016
    internal faces:   2348082
    cells:            841637
    faces per cell:   5.94211
    boundary patches: 6
    point zones:      0
    face zones:       0
    cell zones:       0

Overall number of cells of each type:
    hexahedra:     792917
    prisms:        44780
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     3940
    Breakdown of polyhedra by number of faces:
        faces   number of cells
            4   4
            5   3936

Checking topology...
    Boundary definition OK.
 ***Total number of faces on empty patches is not divisible by the number of cells in the mesh. Hence this mesh is not 1D or 2D.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces...
                   Patch    Faces   Points                  Surface topology
            frontAndBack    33720    37963  ok (non-closed singly connected)
                    left    10000    10251  ok (non-closed singly connected)
                   right    10000    10251  ok (non-closed singly connected)
                  bottom     3026     3561  ok (non-closed singly connected)
                     top     4712     5452  ok (non-closed singly connected)
              fixedWalls   243476   249736  multiply connected (shared edge)
  <<Writing 2 conflicting points to set nonManifoldPoints

Checking geometry...
    Overall domain bounding box (-0.17 -0.0604041 -0.001) (0.17 0.0601678 0.001)
    Mesh has 2 geometric (non-empty/wedge) directions (1 1 0)
    Mesh has 2 solution (non-empty) directions (1 1 0)
 ***Number of edges not aligned with or perpendicular to non-empty directions: 928948
  <<Writing 951037 points on non-aligned edges to set nonAlignedEdges
    Boundary openness (-2.86088e-16 1.1772e-16 -1.21395e-15) OK.
    Max cell openness = 7.07551e-16 OK.
    Max aspect ratio = 12.3976 OK.
    Minimum face area = 1.35674e-09. Maximum face area = 2.45047e-06.  Face area magnitudes OK.
    Min volume = 6.42698e-13. Max volume = 9.79806e-11.  Total volume = 3.44166e-05.  Cell volumes OK.
    Mesh non-orthogonality Max: 77.2055 average: 16.6713
   *Number of severely non-orthogonal (> 70 degrees) faces: 28.
    Non-orthogonality check OK.
  <<Writing 28 non-orthogonal faces to set nonOrthoFaces
 ***Error in face pyramids: 1 faces are incorrectly oriented.
  <<Writing 1 faces with incorrect orientation to set wrongOrientedFaces
 ***Max skewness = 7.85662, 2557 highly skew faces detected which may impair the quality of the results
  <<Writing 2557 skew faces to set skewFaces
    Coupled point location match (average 0) OK.

Failed 3 mesh checks.

温

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.1                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 4.1
Exec   : simpleFoam
Date   : Apr 10 2017
Time   : 15:01:18
Host   : "11"
PID    : 9444
Case   : /home/w11/OpenFOAM/w11-4.1/run/ASBM2-Da
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0


SIMPLE: convergence criteria
    field p	 tolerance 1e-06
    field U	 tolerance 1e-06

Reading field p

Reading field U

Reading/calculating face flux field phi

Selecting incompressible transport model Newtonian
Selecting turbulence model type laminar
No MRF models present

No finite volume options present


Starting time loop

Time = 1

smoothSolver:  Solving for Ux, Initial residual = 1, Final residual = 9.33846e-13, No Iterations 136
smoothSolver:  Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0
GAMG:  Solving for p, Initial residual = 1, Final residual = 0.0975624, No Iterations 26
time step continuity errors : sum local = 0.00312299, global = -0.000382393, cumulative = -0.000382393
ExecutionTime = 11.95 s  ClockTime = 12 s

.........

Time = 80

smoothSolver:  Solving for Ux, Initial residual = 0.564078, Final residual = 8.76275e-13, No Iterations 103
smoothSolver:  Solving for Uy, Initial residual = 0.391492, Final residual = 9.39228e-13, No Iterations 97
GAMG:  Solving for p, Initial residual = 0.990623, Final residual = 0.617109, No Iterations 1000
time step continuity errors : sum local = 1.38438e+20, global = 5.64087e+19, cumulative = 5.64087e+19
ExecutionTime = 1160.33 s  ClockTime = 1164 s

Time = 81

smoothSolver:  Solving for Ux, Initial residual = 0.414375, Final residual = 3.94608e-10, No Iterations 1000
smoothSolver:  Solving for Uy, Initial residual = 0.468273, Final residual = 2.39705e-10, No Iterations 1000
#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::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  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 ??:?
#5  Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#6  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
#7  Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:?
#8  Foam::fvMatrix<double>::solve() at ??:?
#9  ? at ??:?
#10  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#11  ? at ??:?
浮点数例外 (核心已转储)


这是我的fvSolution文件
solvers 
{

    U
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-12;
        relTol           0;
        nSweeps          1;
    }

    p
    {
        solver           GAMG;
        tolerance        1e-9;
        relTol           0.1;
        smoother         GaussSeidel;
        nPreSweeps       0;
        nPostSweeps      2;
        cacheAgglomeration on;
        agglomerator     faceAreaPair;
        nCellsInCoarsestLevel 10;
        mergeLevels      1;
    }

}


SIMPLE
{
    nNonOrthogonalCorrectors 0;

    residualControl
    {
        p               1e-6;
        U               1e-6;
    }

	pRefCell 0;
	pRefValue 0;
}

relaxationFactors
{
    p               0.2;
    U               0.9;
}

这个问题困扰了我好几天，本人小白一枚，年初刚接触OpenFOAM，之前做过几次小的模拟没遇到过这种情况，请教各位大神如何解决，感激不尽。

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