ICEM建模

1. 本研究基于ICEM建模，首先在构建计算域两侧循环壁面时 (称源面；source) 要和后续OpenFOAM中循环壁面的名字不同；OpenFOAM中重命名的循环壁面被称新面(new)：
1. ICEM进行循环设置：先在Global Mesh Setup—》Global Mesh Parameters 里设置periodicity
  
  进行网格更新和生成：

OpenFOAM

1. 在OpenFOAM中进行网格转化： " fluentMeshToFoam 文件名.msh "。通过checkMesh，无报错：

checking geometry...
    Overall domain bounding box (-1.925 -0.60993 -0.05) (2.98 0.16507 0.0500586)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness(1.79143e-17 -2.73076e-15 7.27475e-15) 0K.
    Max cell openness = 4.16732e-16 0K.
    Max aspect ratio = 30.0788 0K.
    Minimum face area = 1.31023e-06. 
    Maximum face area = 0.00216234. 
    Face areamagnitudes OK.
    Min volume = 4.46199e-09,Max volume = 697531e-06. Total volume = 0.371859. Cell volumes OK.
    Mesh non-orthogonality Max: 38.5733 average: 2.71723
    Non-orthogonality check OK.Face pyramids OK.
    Max skewness = 0.530396 0K.
    Coupled point location match (average o) OK.
Mesh OK
End

1. 检查"boudnary"，这时的壁面类型是 wall，需要改进：

RIGHT
{
    type      wall;
    inGroups  List<word> 1(wall);
    nFaces    17939;
    startFace 1669453;
}
LEFT
{
    type      wall;
    inGroups  List<word> 1(wall);
    nFaces    17939;
    startFace 1687392;
}

1. 如果直接在"boundary"文件里修改：

RIGHT
{
    type           cyclic;
    inGroups       1(cyclic);
    nFaces         17939;
    startFace      1669453;
    neighbourPatch LEFT;
}
LEFT
{
    type           cyclic;   
    inGroups       1(cyclic);   
    nFaces         17939;  
    startFace      1687392;  
    neighbourPatch RIGHT; 
}

1. 进行 checkMesh，报错：

  **Error in coupled point location: 3 faces have their 0th or consecutive vertex not opposite their coupled equivalent. Average mismatch 4.63216e-07.
  <<Writing 3 faces with incorrectly matched 0th (or consecutive) vertex to set coupledFaces

Failed 1 mesh checks.

End

1. 尽管在 ICEM 中进行了结构网格划分，严格对等。但是由于网格数量较大，导入到 OpenFOAM中很容易出现不兼容，报错现象。这时候，需要通过 "createPatchDict"文件对循环壁面进行设置，"createPatchDict"文件需要放到 system目录下：

pointSync false;
// Patches to create.
patches
(
    {
        // Name of new patch (最好与源面的名字不同，例如示例中的CYCLIC1 (new)和LEFT(source))
        name CYCLIC1:
        // Type of new patch
        patchInfo
        {
            type            cyclic;
            neighbourPatch  CYCLIC2;
            matchTolerance  0.002;
        }

        constructfrom patches;
        patches (LEFT);   //源面
        set f0;
    }
    {
        name CYCLIC2:
        patchInfo
        {
            type            cyclic;
            neighbourPatch  CYCLIC1;
            matchTolerance  0.002;
        }

        constructfrom patches;
        patches (RIGHT); 
        set f0;
    }
);

1. 设置完成后，要运行 createPatch。在本案例中生成了一个新的 "0.001" 文件。里面为重新生成的 "polyMesh" 文件，在"boundary"文件包含了正确的循环壁面类型(源面"LEFT" 和"RIGHT"变成了新面"CYCLIC1"和"CYCLIC2")：

CYCLIC1
{
    type           cyclic;
    inGroups       List<word> 1(cyclic);
    nFaces         17939;
    startFace      1669453;
    matchTolerance 0.002;
    neighbourPatch CYCLIC2;
    transformType  translational;
    separation     (-1.707449737153865e-10 1.376923575158173e-11 -0.1000000014894364);
}
CYCLIC2
{
    type           cyclic;
    inGroups       List<word> 1(cyclic);
    nFaces         17939;
    startFace      1687392;
    matchTolerance 0.002;
    neighbourPatch CYCLIC1;
    transformType  translational;
    separation     (1.707449737153865e-10 -1.376923575158173e-11 0.1000000014894364);
}

1. 把正确的"polyMesh"替换到"constant"文件中，重新 checkMesh，没报错：

Checking geometry ...
    Overall domain bounding box (-1.925 -0.60993 -0.05) (2.98 0.16507 0.0500586)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (1.79143e-17 -2.73076e-15 1.01788e-14) 0K.
    Max cell openness = 4.16732e-16 0K.
    Max aspect ratio'= 30.0788 0K.
    Minimum face area = 1.31023e-06. Maximum face area = 0.00216234. Face area magnitudes oK.
    Min volume = 4.46199e-09.  Max volume = 6.97531e-06.  Total volume = 0.371859.   Cell volumes OK.
    Mesh non-orthogonality Max: 38.5733 average: 2.70242
    Non-orthogonality  check OK.
    Face pyramids OK.
    Max skewness = 0.530396 0K.
    Coupled point location match (average 4.63138e-07) OK.

Mesh OK.

End

参考文献：
本次教程解决了我面临的问题，主要结合以下教程：
ICEM 部分：

1. CFD中文网：
  链接文本

OpenFOAM部分：

1. CFDonline：
  链接文本
  附件：createPatchDict.gz
1. 知乎：
  链接文本
  附件：channel_v0.4.tar.gz
1. CSDN：
  链接文本

CFD中文网

Zhoujq