虽然blockMesh和snappyHexMesh是强大的网格生成工具，但用户可能经常使用第三方网格划分工具来定义和离散更复杂的流域。

2.3.1 从第三方网格软件包转换

许多高级外部网格化实用程序在网格生成过程中为用户提供了额外的控制级别。这包括可选元素类型、拟合边界层网格和长度比例控制等。某些网格生成器可以直接导出为功能OpenFOAM网格格式。下面列出了OpenFOAM-3.0中支持转换的网格格式的汇编：

Ansys

CFX

Fluent

GMSH

Gambit

Ideas

Kiva

Netgen

Plot3D

Star-CD

tetgen

KIVA

导入实用程序的功能以及它们使用的命名法差别很大。Fluent导入工具将内部边界转换为faceSet，而其他工具完全忽略此类特征。

由于许可证问题，用于从Star CCM+导入网格的网格转换工具及其相关库需要手动下载和编译，而不是通过Allrun脚本。

如果您的特定网格化软件未在上述列表中提及，则它很可能能够将网格导出为支持的中间格式。

上面提到的所有转换实用程序的源代码可以在这里找到: $W M_{P} RO J EC T_{D} I R / a ppl i c a t i o n s / u t i l i t i es / m es h / co n v ers i o n / 。用户还可以选择使用 f o am M es h T o Fl u e n t 和 f o am T o St a r M es h 实用工具将 Op e n FO A M 网格转换为 Fl u e n t 或 St a r - C D 网格格式。这对于导出从前面提到的 s na pp yHe x M es h 实用程序生成的网格特别有用。网格转换过程通常非常简单，不同转换实用程序之间的语法变化很小。出于这个原因，将只给出一个例子，并将基于 f l u e n tM es h T o F o am 转换实用程序。要开始这个过程，请将教程案例复制到选择的目录中，本教程基于 i co F o am 求解器现有的网格转换教程。 ‘‘‘ ba s h ? > c p - r$ FOAM_TUTORIALS/incompressible/icoFoam/elbow/ meshConversionTest ?> cd meshConversionTest


转换网格非常简单，只需运行转换实用程序并将网格文件作为参数传递，该参数必须存在于目录中。 在转换过程中，Utility将向控制台输出补丁名称和网格统计信息。 Polymesh目录中包含的文件将相应更新。 

```bash
?>  fluentMeshToFoam elbow.msh

重要的是要记住，导入的网格只和导出的网格一样好。对于Fluent网格，由于OpenFoam只支持三维网格，所以不可能导入2D网格。导入完成后，需要更新case，以反映初始和边界条件文件中的新修补程序名称。所有现有的补丁可以从导入工具的输出中收集，也可以通过编辑器打开constant/polymesh/boundary手动查找。对于本教程，U和P物理场是为这个特定的网格预先配置的。

在导入过程中缩放网格就像在命令中添加选项和缩放因子一样简单。为了本教程，网格应该缩小一个数量级。

?>  fluentMeshToFoam -scale 0.1 elbow.msh

在许多第三方网格划分工具中构造网格时，用户通常可以为每个特定的贴片分配边界条件类型，如入口、出口、壁面等。转换过程将尝试将某些边界条件格式匹配到相应的OpenFoam格式，但不能保证边界条件转换的成功或准确性。检查转换是否正确解析了流信息是至关重要的。要检查这一点，请检查constant/polymesh/boundary，并在新转换的网格上运行checkmesh。

空腔实例简化草图

2.3.2 从二维网格到轴对称网格的转换

为了将网格转换为轴对称网格，必须满足以下要求。网格必须已经是一个有效的OpenFOAM网格，它必须只有一个网格“厚”。后一个要求对OpenFOAM中的所有二维网格都有效。由于icoFoam的腔体示例满足所有这些要求，因此本教程使用它。它位于$foam_tutorials/incompressible/icofoam/cavity。

由于网格形状为矩形并且只有一个单元，因此可以创建非常基本的几何体。在OpenFOAM中，轴对称网格具有以下属性：网格为一个单元“厚”，并绕对称轴旋转以形成5°楔形。楔形体的两个成角度边界被视为楔形体类型的单独patch。

makeAxialMesh的来源可在OpenFOAM wiki上找到：http://openfoamwiki.net/index.php/Contrib_MakeAxialMesh。按照其中的说明下载并编译该实用程序。

接下来的步骤是在您选择的工作目录中创建案例文件夹的副本，重命名该目录以避免将来发生任何混淆，然后创建2D基础网格。

?>  cp -r <span class="katex"><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.02778em;">FO</span><span class="mord mathnormal">A</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.10903em;">M</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3283em;"><span style="top:-2.55em;margin-left:-0.109em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.13889em;">T</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.10903em;">U</span><span class="mord mathnormal" style="margin-right:0.00773em;">TOR</span><span class="mord mathnormal" style="margin-right:0.07847em;">I</span><span class="mord mathnormal">A</span><span class="mord mathnormal">L</span><span class="mord mathnormal" style="margin-right:0.05764em;">S</span><span class="mord">/</span><span class="mord mathnormal">u</span><span class="mord mathnormal">t</span><span class="mord mathnormal">i</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal">i</span><span class="mord mathnormal">es</span><span class="mord">/</span><span class="mord mathnormal">in</span><span class="mord mathnormal">co</span><span class="mord mathnormal">m</span><span class="mord mathnormal">p</span><span class="mord mathnormal">ress</span><span class="mord mathnormal">ib</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord">/</span><span class="mord mathnormal">i</span><span class="mord mathnormal">co</span><span class="mord mathnormal" style="margin-right:0.13889em;">F</span><span class="mord mathnormal">o</span><span class="mord mathnormal">am</span><span class="mord">/</span><span class="mord mathnormal">c</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.03588em;">y</span><span class="mord">.</span><span class="mclose">?</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">m</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">c</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.03588em;">y</span><span class="mord mathnormal">a</span><span class="mord mathnormal">x</span><span class="mord mathnormal">i</span><span class="mord mathnormal" style="margin-right:0.05764em;">S</span><span class="mord mathnormal" style="margin-right:0.03588em;">y</span><span class="mord mathnormal">m</span><span class="mord mathnormal" style="margin-right:0.07153em;">C</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.03588em;">y</span><span class="mclose">?</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">c</span><span class="mord mathnormal">d</span><span class="mord mathnormal">a</span><span class="mord mathnormal">x</span><span class="mord mathnormal">i</span><span class="mord mathnormal" style="margin-right:0.05764em;">S</span><span class="mord mathnormal" style="margin-right:0.03588em;">y</span><span class="mord mathnormal">m</span><span class="mord mathnormal" style="margin-right:0.07153em;">C</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.03588em;">y</span><span class="mclose">?</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.9805em;vertical-align:-0.2861em;"></span><span class="mord mathnormal">b</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">oc</span><span class="mord mathnormal" style="margin-right:0.03148em;">k</span><span class="mord mathnormal" style="margin-right:0.10903em;">M</span><span class="mord mathnormal">es</span><span class="mord mathnormal">h</span><span class="mord">‘‘‘</span><span class="mord cjk_fallback">对于轴对称网格，</span><span class="mord mathnormal">m</span><span class="mord mathnormal">o</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">in</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">Wa</span><span class="mord mathnormal" style="margin-right:0.01968em;">ll</span><span class="mord cjk_fallback">面片被用作对称轴（参见图</span><span class="mord">2.24</span><span class="mord cjk_fallback">）。此外，单个</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">ro</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord mathnormal">A</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.05017em;">B</span><span class="mord mathnormal">a</span><span class="mord mathnormal">c</span><span class="mord mathnormal" style="margin-right:0.03148em;">k</span><span class="mord cjk_fallback">面片将被分割，并充当楔形体的两个边界（</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">ro</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord mathnormal">A</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.05017em;">B</span><span class="mord mathnormal">a</span><span class="mord mathnormal">c</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.03148em;">k</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.1514em;"><span style="top:-2.55em;margin-left:-0.0315em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight">n</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord cjk_fallback">与</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">ro</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord mathnormal">A</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.05017em;">B</span><span class="mord mathnormal">a</span><span class="mord mathnormal">c</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.03148em;">k</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.1514em;"><span style="top:-2.55em;margin-left:-0.0315em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight">p</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2861em;"><span></span></span></span></span></span></span><span class="mord mathnormal">os</span><span class="mord cjk_fallback">）。在命令行中输入的参数反映了这一点：</span><span class="mord">‘‘‘</span><span class="mord mathnormal">ba</span><span class="mord mathnormal">s</span><span class="mord mathnormal">h</span><span class="mclose">?</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal" style="margin-right:0.03148em;">mak</span><span class="mord mathnormal">e</span><span class="mord mathnormal">A</span><span class="mord mathnormal">x</span><span class="mord mathnormal">ia</span><span class="mord mathnormal" style="margin-right:0.10903em;">lM</span><span class="mord mathnormal">es</span><span class="mord mathnormal">h</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">−</span><span class="mspace" style="margin-right:0.2222em;"></span></span><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">a</span><span class="mord mathnormal">x</span><span class="mord mathnormal">i</span><span class="mord mathnormal">s</span><span class="mord mathnormal">m</span><span class="mord mathnormal">o</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">in</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">Wa</span><span class="mord mathnormal" style="margin-right:0.01968em;">ll</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">−</span><span class="mspace" style="margin-right:0.2222em;"></span></span><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal">e</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">ro</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord mathnormal">A</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.05017em;">B</span><span class="mord mathnormal">a</span><span class="mord mathnormal">c</span><span class="mord mathnormal" style="margin-right:0.03148em;">k</span><span class="mord">‘‘‘</span><span class="mord cjk_fallback">该工具将创建一个新的时间目录（在本例中为</span><span class="mord">0.005</span><span class="mord cjk_fallback">）来存储转换后的网格。如果创建未按预期工作，则只需删除此目录，并再次恢复基本网格。案例目录现在应包含如下所示的文件夹：</span><span class="mord">‘‘‘</span><span class="mord mathnormal">ba</span><span class="mord mathnormal">s</span><span class="mord mathnormal">h</span><span class="mclose">?</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">s</span><span class="mord">00.005</span><span class="mord mathnormal">co</span><span class="mord mathnormal">n</span><span class="mord mathnormal">s</span><span class="mord mathnormal">t</span><span class="mord mathnormal">an</span><span class="mord mathnormal">t</span><span class="mord mathnormal">sys</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mord mathnormal">m</span><span class="mord">‘‘‘</span><span class="mord cjk_fallback">此时，网格已弯曲成</span><span class="mord">5°</span><span class="mord cjk_fallback">楔形，如图</span><span class="mord">2.25</span><span class="mord cjk_fallback">所示。但是，</span><span class="mord mathnormal">m</span><span class="mord mathnormal">o</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">in</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">Wa</span><span class="mord mathnormal" style="margin-right:0.01968em;">ll</span><span class="mord cjk_fallback">面片中的面仍然存在，但它们现在被挤压为面面积接近于零的面。</span><span class="mord mathnormal" style="margin-right:0.03148em;">mak</span><span class="mord mathnormal">e</span><span class="mord mathnormal">A</span><span class="mord mathnormal">x</span><span class="mord mathnormal">ia</span><span class="mord mathnormal" style="margin-right:0.10903em;">lM</span><span class="mord mathnormal">es</span><span class="mord mathnormal">h</span><span class="mord cjk_fallback">变换点位置，但不改变网格连接。因此，对称面片没有指定面（</span><span class="mord mathnormal">n</span><span class="mord mathnormal" style="margin-right:0.13889em;">F</span><span class="mord mathnormal">a</span><span class="mord mathnormal">ces</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">0</span><span class="mord cjk_fallback">），必须移除。</span><span class="mclose">!</span><span class="mopen">[</span><span class="mord cjk_fallback">图</span><span class="mord">2.25</span><span class="mord cjk_fallback">：</span><span class="mord mathnormal" style="margin-right:0.03148em;">mak</span><span class="mord mathnormal">e</span><span class="mord mathnormal">A</span><span class="mord mathnormal">x</span><span class="mord mathnormal">ia</span><span class="mord mathnormal" style="margin-right:0.10903em;">lM</span><span class="mord mathnormal">es</span><span class="mord mathnormal">h</span><span class="mord cjk_fallback">楔形块变换前后的</span><span class="mord">2</span><span class="mord mathnormal" style="margin-right:0.02778em;">D</span><span class="mord cjk_fallback">型腔网格</span><span class="mclose">]</span><span class="mopen">(</span><span class="mord mathnormal">h</span><span class="mord mathnormal">ttp</span><span class="mord mathnormal">s</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">:</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">//</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">a</span><span class="mord mathnormal">ee</span><span class="mord">0</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">−</span><span class="mspace" style="margin-right:0.2222em;"></span></span><span class="base"><span class="strut" style="height:0.8389em;vertical-align:-0.1944em;"></span><span class="mord">1253397841.</span><span class="mord mathnormal">cos</span><span class="mord">.</span><span class="mord mathnormal">a</span><span class="mord mathnormal">p</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">−</span><span class="mspace" style="margin-right:0.2222em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">c</span><span class="mord mathnormal">h</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">d</span><span class="mord mathnormal">u</span><span class="mord">.</span><span class="mord mathnormal">m</span><span class="mord mathnormal" style="margin-right:0.03588em;">y</span><span class="mord mathnormal" style="margin-right:0.03588em;">q</span><span class="mord mathnormal">c</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">o</span><span class="mord mathnormal">u</span><span class="mord mathnormal">d</span><span class="mord">.</span><span class="mord mathnormal">co</span><span class="mord mathnormal">m</span><span class="mord">/</span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal">i</span><span class="mord mathnormal" style="margin-right:0.04398em;">z</span><span class="mord mathnormal">im</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord">/202212030308697.</span><span class="mord mathnormal">p</span><span class="mord mathnormal">n</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mclose">)</span><span class="mord cjk_fallback">在这种情况下，建议使用</span><span class="mord mathnormal">co</span><span class="mord mathnormal" style="margin-right:0.01968em;">ll</span><span class="mord mathnormal">a</span><span class="mord mathnormal">p</span><span class="mord mathnormal">se</span><span class="mord mathnormal" style="margin-right:0.05764em;">E</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">es</span><span class="mord cjk_fallback">工具。它需要两个必需的命令行参数：边长和合并角：</span><span class="mord">‘‘‘</span><span class="mord mathnormal">ba</span><span class="mord mathnormal">s</span><span class="mord mathnormal">h</span><span class="mclose">?</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">co</span><span class="mord mathnormal" style="margin-right:0.01968em;">ll</span><span class="mord mathnormal">a</span><span class="mord mathnormal">p</span><span class="mord mathnormal">se</span><span class="mord mathnormal" style="margin-right:0.05764em;">E</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">es</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&lt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">e</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">t</span><span class="mord mathnormal">h</span><span class="mopen">[</span><span class="mord mathnormal">m</span><span class="mclose">]</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;&lt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">m</span><span class="mord mathnormal" style="margin-right:0.02778em;">er</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">e</span><span class="mord mathnormal">an</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mopen">[</span><span class="mord mathnormal">d</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">rees</span><span class="mclose">]</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord">‘‘‘</span><span class="mord cjk_fallback">在许多应用中，边长为</span></span></span></span>1 × 10^{−8}$米，合并角为179°时，可以正确识别和移除最近塌陷的面。在网格边长比例极小的某些情况下，可能需要较小的边长以避免误报和无意中删除有效边。对于本示例，使用所示参数执行collapseEdges不会出现问题。

```bash
?>  collapseEdges -latestTime 1e-8 179

对于一些最终的内务处理，建议从边界列表中删除现在为空的面片。打开constant/polyMesh/boundary并删除movingWall与frontAndBack条目。请注意，它们被列为包含零个面：nFaces 0;。将边界列表大小变更为3，以反映这两项删除。边界文件现在应类似于：

3
(
    fixedWalls
    {
        type            wall;
        nFaces            60;
        startFace        760;
    }
    frontAndBack_pos
    {
        type            wedge;
        nFaces           400;
        startFace        820;
    }
    frontAndBack_neg
    {
        type            wedge;
        nFaces          400;
        startFace       1220;
    }
)

此时，可以使用autoPatch工具将fixedWalls面片分割为3个单独的面片。这将查看连续的面片，并尝试根据给定的特征角度确定适当的位置来分割它。

在这种情况下，任何形成大于30°角的patch边都可以被分割以形成新的patch。在分配边界条件时，这提供了更大的灵活性。

?>  autoPatch -latestTime 30

分割后将重命名面片。-latestTime标志将仅读取可用的最新时间步。分割网格面会储存在另一个时间步长目录中，而不是覆写时间步长。最后，应使用checkMesh工具检查网格是否存在错误，这应被视为最佳实践的一般规则：更改网格时始终运行checkMesh。